JP2018183768A - Purifier and purification method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a purifier and a purification method capable of suppressing self-decomposition of dissolved ozone in ground water in the soil, and improving acceleration of in-situ decomposition and removal of a contaminant contained in the ground water in the soil.SOLUTION: A purifier for purifying ground water in the soil, includes a sparging well 1 inserted into the soil, a first supply part 2 for supplying ozone gas into the sparging well 1, and a second supply part 3 for supplying, for example, inorganic carbon into the sparging well 1, as a continuity body for suppressing decomposition of ozone in the ground water.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a purification device and a purification method for purifying contamination of groundwater in soil.

  In groundwater contamination surveys at factory sites, etc., groundwater contamination by organic substances has become apparent. Examples of the pollutants include organochlorine compounds such as tetrachlorethylene (also referred to as PCE) and trichlorethylene (abbreviated as TCE) classified as volatile organic compounds (hereinafter referred to as “VOC”). One method for purifying these substances is an air sparging process in which air is diffused from a well installed in the ground into the groundwater.

  In the air sparging process, the VOC in the groundwater moves from the liquid layer to the gas layer using the concentration gradient at the gas-liquid interface between the bubbles diffused in the groundwater and the groundwater as a driving force. The gasified VOC rises in the soil with bubbles and is discharged to the ground. In this treatment method, the air diffused in the groundwater passes through a position where it easily flows in the soil, so that the entire contaminated area cannot be air sparged. Accordingly, VOC or the like remains in the groundwater in the contaminated area only by the air sparging process.

  Therefore, an in-situ purification method of groundwater using an ozonized oxygen (hereinafter referred to as “ozone”) gas as a sparging gas diffused into the groundwater has been proposed (see, for example, Patent Documents 1 and 2). This treatment method is a method for purifying groundwater using the oxidizing power of ozone in addition to the removal of VOC by air sparging treatment. The ozone gas injected into the groundwater moves from the gas side to the liquid side due to the concentration gradient at the gas-liquid interface between the bubbles and the groundwater. And the ozone melt | dissolved in groundwater permeate | disassembles and removes VOC in-situ by penetrating into the soil where air bubbles are difficult to pass as ozone water. All of the conventional groundwater purification devices using ozone gas promote the decomposition of dissolved ozone in the groundwater, and generate radicals having higher oxidizing power than ozone, thereby improving the VOC decomposition rate. It is.

JP 2008-272575 A Japanese Patent Laying-Open No. 2015-57267

  According to the conventional purification device and the purification method, the above-described radical disappears rapidly, and there is a problem that the decomposition efficiency of the pollutant in the groundwater in the soil does not last and does not reach the original position of the pollutant.

  The present invention has been made to solve the above-mentioned problems, suppresses the self-decomposition of dissolved ozone in groundwater in soil, and improves the in-situ degradation and removal of contaminants in groundwater in soil. It is an object of the present invention to provide a possible purification device and purification method.

The purification device of the present invention is a purification device for purifying groundwater in soil, a sparging well inserted into the soil, a first supply unit for supplying ozone to the sparging well, and sustaining for suppressing decomposition of ozone A second supply for supplying body to the sparging well;
A control unit that controls the first supply unit and the second supply unit is provided.
Further, the purification method of the present invention is a purification method for purifying groundwater in soil, wherein a first step of supplying ozonized oxygen gas to the groundwater and a sustaining body that suppresses decomposition of ozone are supplied to the groundwater. And a second step.

  According to the purification device and the purification method of the present invention, it is possible to suppress the self-decomposition of dissolved ozone in the groundwater in the soil and improve the in-situ decomposition and removal of the contaminants of the groundwater in the soil.

It is a figure which shows the structure of the purification apparatus of Embodiment 1 of this invention. It is a figure which shows the structure of the sparging well of the purification apparatus shown in FIG. It is a figure which shows the timing chart of the purification method using the purification apparatus shown in FIG. It is a figure which shows the timing chart of the purification method using the purification apparatus shown in FIG. It is a figure which shows the relationship between the inorganic carbonic acid density | concentration in the purification apparatus shown in FIG. 1, and the half life of dissolved ozone concentration. It is a figure which shows the structure of the purification apparatus of Embodiment 2 of this invention. It is a figure which shows the timing chart of the purification method using the purification apparatus shown in FIG. It is a figure which shows the timing chart of the purification method using the purification apparatus shown in FIG. It is a figure which shows the structure of the purification apparatus of Embodiment 3 of this invention. It is a figure which shows the timing chart of the purification method using the purification apparatus shown in FIG. It is a figure which shows the timing chart of the purification method using the purification apparatus shown in FIG. It is a figure which shows the timing chart of the purification method using the purification apparatus shown in FIG. It is a figure which shows the structure of the Example of the purification apparatus of each embodiment of this invention. It is a figure which shows the experimental condition in the purification apparatus shown in FIG. It is a figure which shows the experimental condition in the purification apparatus shown in FIG. It is a flowchart which shows the purification method of Embodiment 1 of this invention. It is a flowchart which shows the purification method of Embodiment 2 of this invention. It is a flowchart which shows the purification method of Embodiment 3 of this invention. It is a figure which shows the structure of the purification apparatus of Embodiment 4 of this invention. It is a schematic diagram which shows the time-dependent change of the ozone gas concentration contained in the gas in soil.

Embodiment 1 FIG.
Embodiments of the present invention will be described below. The purification apparatus according to the embodiment of the present invention is applied to a process for purifying in-situ groundwater contamination by contaminants such as VOC using ozone gas as a sparging gas in a gas sparging method. The gas sparging method is a groundwater purification method that volatilizes pollutants (for example, volatile organic substances) in the groundwater by blowing gas into the groundwater, and collects both the volatilized contaminants (organic substances) and gas. Sure. Therefore, when gas is injected into the groundwater, the pollutants that have been volatilized and gasified are taken into the bubbles of the injected gas, become bubbles, rise in the groundwater, and reach the groundwater surface. Air bubbles that reach the groundwater surface are sucked by installing a suction well, or by sucking gas from the ground surface using a cover installed on the ground surface of the soil, as a pollutant (volatile organic substance) ).

  And in the embodiment of the present invention, the “sustained body” that suppresses the self-decomposition of dissolved ozone in which ozone gas is dissolved in groundwater, in the groundwater in the soil, together with the ozone gas used as the sparging gas shown above, or It is supplied individually. The sustaining substance is a substance that suppresses the self-decomposition of dissolved ozone in which ozone gas is dissolved in groundwater and extends the half-life of the dissolved ozone concentration in groundwater. The half-life of the dissolved ozone concentration is the time required for the dissolved ozone concentration to be reduced to half, and the longer the half-life of the dissolved ozone concentration, the longer the dissolved ozone in the groundwater. The details of the sustaining body will be described later. For example, at least one of inorganic carbonic acid, carbon dioxide gas, monohydric alcohol, and acid solution is included, and two or more of them may be used at the same time.

  FIG. 1 is a diagram illustrating the configuration of a purification device according to Embodiment 1 of the present invention. In the figure, a contaminated area 100 indicates an area in which groundwater is contaminated by contaminants (such as VOC) in the soil. The sparging well 1 (hereinafter referred to as well 1) is a well inserted into the contaminated region 100. The sparging well 1 is composed of a pipe embedded in soil, and some soil may exist in the pipe. The pipe buried in the soil is made of, for example, a material of stainless steel, polyvinyl chloride, or fluororesin having ozone resistance, and includes a jetting part 11 that injects gas into the groundwater at the lower end side. Furthermore, it is good also as a structure which sucks the gas which reached | attained the ground surface using the cover installed in the soil on the ground water surface with the suction well which attracts | sucks the gas in soil with the sparging well 1. .

  In some cases, a plurality of wells 1 are installed in the contaminated area 100. Here, one well 1 will be described as an example. A first supply unit 2 and a second supply unit 3 are connected to the well 1. The first supply unit 2 is for supplying ozone gas to the well 1. In order to supply ozone gas, the first supply unit 2 supplies, for example, an ozone generator for generating ozone gas from oxygen gas, and an oxygen gas supply for supplying oxygen gas as a raw material for generating ozone gas to the ozone generator. Mechanism, ozone gas concentration meter for measuring the concentration of ozone gas generated by ozone generator, ozone decomposition catalyst mechanism for decomposing ozone gas into oxygen gas, and adjusting the flow rate of ozone gas generated by ozone generator It is composed of a flow rate adjustment mechanism. The supply pressure of the ozone gas is adjusted and supplied by an oxygen gas supply mechanism that supplies oxygen gas to the ozone generator, a mechanism that is installed in the ozone generator, or a mechanism that is installed downstream from the ozone generator. The Moreover, it is good also as a structure provided with the ozone gas storage mechanism which stores the ozone gas produced | generated with the ozone generator.

  The second supply unit 3 is for supplying the sustaining body to the well 1. In the case where inorganic carbonate is used as the sustaining body, the second supply unit 3 includes, for example, a storage unit that stores an inorganic carbonate aqueous solution and an adjustment mechanism that adjusts the supply amount of the inorganic carbonate aqueous solution discharged from the storage unit. . The well 1 and the first supply unit 2 are connected by a first pipe 51. The well 1 and the second supply unit 3 are connected by a second pipe 52 via a first pipe 51.

  The control unit 4 controls the first supply unit 2 and the second supply unit 3. The control unit 4 and the first supply unit 2 are connected via a first signal line 81. The control unit 4 and the second supply unit 3 are connected via a second signal line 82. The control unit 4 is configured by a personal computer, for example. The control unit 4 controls the supply of ozone gas from the first supply unit 2 by transmitting a signal to, for example, a flow rate adjusting mechanism and an ozone generator of the first supply unit 2 through the first signal line 81. The control unit 4 transmits a signal to, for example, the adjustment mechanism of the second supply unit 3 through the second signal line 82 to control the supply of the sustaining body from the second supply unit 3.

  On the lower end side of the well 1, a jetting part 11 for supplying ozone gas and a sustaining body to groundwater is formed. As for the ejection part 11, the hole or slit formed in the piping of the well 1 is formed in one or more places. The well 1 is provided with a sealing member at the upper end of the well 1 so that the ozone gas and the sustaining body supplied from the supply units 2 and 3 do not leak from the upper end of the well 1 to the outside air (atmosphere). (Atmosphere) is configured to maintain a state that does not leak. This prevents the ozone gas and the sustaining body from leaking from the top of the well 1 into the outside air (atmosphere).

  As shown in FIG. 2, the first pipe 51 and the second pipe 52 may have a configuration in which the first pipe 51 and the second pipe 52 are arranged in the well 1 without connecting the first pipe 51 and the second pipe 52. The lower ends of the first pipe 51 and the second pipe 52 inserted into the well 1 may extend to the vicinity of the ejection part 11. At this time, the lower end of the second pipe 52 is installed to be below the first pipe 51. This is to prevent the sustaining body, which is the liquid supplied from the second pipe 52, from flowing back to the first pipe 51 for supplying gas. For the sealing member of the first pipe 51, the second pipe 52, and the well 1, a material having high ozone resistance such as fluororesin, stainless steel, and polyvinyl chloride is selected.

  Next, the purification method by the purification apparatus of Embodiment 1 configured as described above will be described based on the flowchart shown in FIG. The control unit 4 controls, for example, a flow rate adjusting mechanism and an ozone generator of the first supply unit 2 via the first signal line 81, and sets a desired supply condition of ozone gas (step ST1 in FIG. 16). Next, the 1st supply part 2 controlled by the control part 4 supplies ozone gas to the underground water of the contaminated area 100 from the ejection part 11 of the lower part of the well 1 via the 1st piping 51 (as 1st process). Step ST2 in FIG. Then, the ozone gas supplied to the groundwater is diffused into the groundwater to become bubbles, and rises in the soil of the contaminated area 100. Then, ozone is dissolved from the bubbles into the groundwater using the concentration gradient between the bubbles and the gas-liquid interface with the groundwater as a driving force.

  The ozone dissolved in the groundwater is consumed for reaction with pollutants (such as VOC) and oxidants in the groundwater, or ozone self-decomposition. Ozone that has not been consumed in these reactions is detected in groundwater as dissolved ozone. Dissolved ozone detected in the groundwater penetrates into the soil together with the groundwater and contributes to the degradation of pollutants. Next, when ozone gas is supplied for a predetermined time, the control unit 4 controls the first supply unit 2 via the first signal line 81 and stops supply of ozone gas (step ST3 in FIG. 16).

  Moreover, the control part 4 controls the adjustment mechanism of the 2nd supply part 3 via the 2nd signal line 82, and sets the supply conditions of a desired persistence body (step ST4 of FIG. 16). Next, the second supply unit 3 controlled by the control unit 4 supplies the sustaining body to the groundwater in the contaminated region 100 from the ejection unit 11 below the well 1 via the second pipe 52 (second). As a process, step ST5 in FIG. Next, when supplying the sustaining body for a predetermined time, the control unit 4 controls the second supplying unit 3 via the second signal line 82 and stops supplying the sustaining body (step ST6 in FIG. 16).

  In the first embodiment, as shown in FIG. 16, as long as it includes a step of supplying ozone gas to groundwater (first step) and a step of supplying sustaining body to groundwater (second step). Often, various examples of the combination and timing of the first step and the second step can be considered. Hereinafter, combinations and timing examples of the first step and the second step will be described with reference to FIGS. 3 and 4.

  Next, the supply and stop timings of the ozone gas and the sustaining body in the purification method of the first embodiment described above will be described based on the timing chart examples of FIGS. 3 and 4. 3 and 4 show a series of operations of the purification method according to the first embodiment of the present invention as one cycle. Specifically, one cycle is divided into an arbitrary number of steps T. Here, when one cycle is divided into two, T1 step and T2 step are respectively shown, and in the operation of each step, the supply and stop settings of ozone gas and the sustaining body are respectively shown.

  The purification method in FIG. 3 supplies a sustaining body to the groundwater in the T1 step (second step), and does not supply ozone gas (stop). Next, in step T2, ozone gas and the sustaining body are simultaneously supplied to the groundwater (simultaneous step of the first step and the second step). In this way, when two or more kinds of fluids of ozone gas and the sustaining body are supplied to the groundwater at the same time, the ejection pressures of the first pipe 51 of the first supply unit 2 and the second pipe 52 of the second supply unit 3 are equal. It is desirable to control. If the two types of ejection pressures are different, there is a possibility that a fluid having a high ejection pressure will flow back through a pipe of a fluid having a low ejection pressure, and if the two types of ejection pressure are made equal, the backflow can be prevented.

  Moreover, the purification method in FIG. 4 supplies a sustaining body to groundwater (2nd process) in T1, and does not supply ozone gas (stop). In step T2, ozone gas is supplied to the ground water (first step), and the sustaining body is not supplied (stop). In the T1 step, since ozone gas is not supplied to groundwater, ozone gas generated by, for example, an ozone generator of the first supply unit 2 may be stored by an ozone gas storage mechanism. In the T2 step, the ozone gas stored in the ozone gas storage mechanism and the ozone gas generated in the ozone generator are simultaneously supplied to the groundwater, so that the ozone generator in the first supply unit 2 generates the ozone gas. It is possible to supply ozone gas with a concentration higher than the concentration of ozone gas to groundwater.

  Next, the time for one cycle shown in FIGS. 3 and 4 will be described. When the amount of groundwater V (L) in the contaminated area 100 and the groundwater flow velocity Q (L / hr) passing through the contaminated area 100, one cycle time is the residence time of groundwater in the contaminated area 100 V / Q (hr) The time is 0.01 to 8 times. Alternatively, when the gas flow rate G (L / hr) to be supplied to the contaminated region 100 is set, one cycle time is 0.01 to 8 times the V / G (hr) of the gas residence time in the contaminated region 100. To do.

  One cycle time is selected from the shorter one of the residence time (V / Q) of the groundwater and the residence time (V / G) of the gas. If the residence time of groundwater in the contaminated area 100 or the residence time of gas is 0.01 times or less, the amount of ozone supplied to the groundwater is insufficient. Further, if the residence time of the groundwater in the contaminated region 100 or the residence time of the gas is 8 times or more, the time for one cycle becomes longer, and excessive excess ozone is supplied to the groundwater, which may increase the cost. As a purification method, after the end of one cycle, the next one cycle may be repeated.

  The measurement of the quality of groundwater in the contaminated area 100 may be performed after the end of one cycle of the purification method, or may be performed every predetermined time. By periodically measuring the quality of groundwater in the contaminated area 100, the supply condition of ozone gas and the supply condition of the sustaining body can be respectively changed.

Next, the ozone gas supplied as described above will be described first. First, the generation concentration of ozone supplied by the first supply unit 2 is 0.1 g / Nm ³ to 1000 g / Nm ³ , more preferably 10 g / Nm ³ to 500 g / Nm ³ . However, in order to make the ozone generation concentration 400 g / Nm ³ or more, it is necessary to store and concentrate ozone once. If the ozone generation concentration is less than 0.1 g / Nm ³ , the amount of ozone supplied to the groundwater is insufficient, and the pollutants in the groundwater cannot be efficiently decomposed. Further, when the ozone generation concentration is 1000 g / Nm ³ or more, the ozone generation efficiency is lowered, the power consumption is increased, and the cost is increased.

Next, the pressure of the ozone gas adjusted by the ozone generator of the first supply unit 2 is 0.1 MPa to 1 MPa, more preferably 0.15 MPa to 0.8 MPa as an absolute pressure at the position of the ejection unit 11. When the gas pressure is less than 0.1 MPa, the pressure is lower than the atmospheric pressure, and ozone gas cannot be efficiently supplied to the groundwater. On the other hand, when the gas pressure is 1 MPa or more, the ozone generation efficiency is lowered, the power consumption is increased, and the cost is increased. Next, the flow rate of the ozone gas supplied to the groundwater per 1 m ³ of soil in the contaminated area 100 is 0.01 L / min to 6000 L / min, preferably 0.1 L / min to 100 L / min. If the flow rate of ozone gas is less than 0.01 L / min, the amount of ozone supplied to groundwater is insufficient, and pollutants in groundwater cannot be efficiently decomposed. Further, when the flow rate of ozone gas is 6000 L / min or more, the amount of raw material gas used for generating ozone is increased, the running cost is increased, and the cost is increased.

  If ozone gas of high concentration is used, a high ozone supply rate (amount of ozone per unit treated water amount) can be achieved with a small ozone gas flow rate. Further, in the case where the contaminated area 100 shown in FIG. 1 advances deep underground and the groundwater pressure is high or the soil is difficult for gas to pass, it is necessary to set the supply gas pressure high in order to supply ozone gas to the groundwater. There is. Thus, when supplying ozone gas at a high pressure, the amount of raw material gas used can be suppressed and the amount of gas discharged to the ground can be suppressed by supplying ozone gas to groundwater at a low gas flow rate.

Next, the sustaining body supplied as described above will be described. As the sustaining body, inorganic carbon dioxide, carbon dioxide gas, monohydric alcohol, or acid solution can be considered. First, when using inorganic carbonic acid as the sustaining body, sodium hydrogen carbonate, sodium carbonate, or an inorganic carbonic acid aqueous solution prepared by mixing these is used. Thereby, bicarbonate ions (HCO ₃ ⁻ ) or carbonate ions (CO ₃ ²⁻ ) are supplied to the groundwater. Moreover, it is the same even if it replaces with inorganic carbonate aqueous solution and carbon dioxide gas is supplied to groundwater.

  If inorganic carbonic acid or carbon dioxide gas is supplied to the groundwater in the contaminated area 100, the inorganic carbonic acid reacts with radicals involved in self-decomposition of dissolved ozone. Thereby, the self-decomposition of dissolved ozone in the groundwater is suppressed, and the dissolved ozone concentration in the groundwater can be maintained. By continuing the dissolved ozone in the groundwater, ozone can reach the position away from the position where the bubbles of ozone gas have passed as ozone water. FIG. 5 shows the relationship between the inorganic carbonic acid concentration and the half-life of the dissolved ozone concentration according to Embodiment 1 of the present invention. The half-life of the dissolved ozone concentration is the time required for the dissolved ozone concentration to be reduced to half as shown above. That is, the longer the half-life of the dissolved ozone concentration, the longer the dissolved ozone lasts in the groundwater.

  As shown in FIG. 5, the half-life of the dissolved ozone concentration is 7 minutes in water having a pH of 7, a water temperature of 20 ° C., and an inorganic carbonate concentration of 0 mg / L. And the half life of dissolved ozone concentration becomes long with the increase in inorganic carbonic acid concentration. At an inorganic carbonate concentration of 50 mg / L, the half-life of the dissolved ozone concentration was extended to 41 minutes. And at the inorganic carbonic acid concentration of 150 mg / L or more, the change in the half-life of the dissolved ozone concentration became small. Accordingly, the inorganic carbonate concentration in the groundwater in the contaminated area 100 is measured, and the inorganic carbonate concentration is adjusted so that the inorganic carbonate concentration in the groundwater in the contaminated area 100 is 10 mg / L to 150 mg / L, more preferably 20 mg / L to 80 mg / L. Or supply carbon dioxide to groundwater.

  By supplying inorganic carbonic acid, when the pH of the groundwater increases and becomes alkaline, an acid solution may be supplied simultaneously with the inorganic carbonic acid to suppress the pH fluctuation of the groundwater from +0.5 to -0.5. . The acid solution is selected from sulfuric acid, hydrochloric acid, and citric acid, and a combination of inorganic carbonic acid and acid can be used as a sustaining substance. Thereby, it can prevent that the pH of groundwater increases and self-decomposition of dissolved ozone is promoted. Moreover, since the inorganic carbonic acid is supplied, it is possible to prevent the pH of the groundwater from being excessively lowered due to the excessive supply of the acid solution.

  When the inorganic carbonate concentration of groundwater in the contaminated area 100 is Z (mg / L) and the amount of groundwater V (L) in the contaminated area 100 is adjusted to 50 mg / L in one cycle, The amount of inorganic carbonic acid X (one cycle) supplied to the groundwater in the contaminated area 100 is obtained from (50 (mg / L) -Z (mg / L)) × V. The total amount of the inorganic carbonic acid X may be supplied to the ground water once per cycle, or may be supplied in two or more times per cycle. In addition, when the inorganic carbonic acid amount X is supplied in two or more times, the supply amount per one time may be equalized, and the first supply amount in one cycle is increased to increase the supply amount after the second time. The supply amount may be reduced.

  As described above, when the inorganic carbonic acid amount X is divided into two or more times and supplied to the groundwater, the supply amount of the inorganic carbonic acid solution per one time is reduced as compared with the case where the total amount is supplied once. The inorganic carbonic acid supplied to the groundwater is diffused into the groundwater of the contaminated area 100 by a flow in which bubbles of ozone gas supplied to the groundwater rise in the soil of the contaminated area 100. As described above, the inorganic carbonate is diffused into the groundwater in the contaminated area 100 while suppressing the local increase in the inorganic carbonate concentration in the contaminated area 100 by reducing the supply amount of inorganic carbonate per time. it can. Thereby, it can suppress that pH of groundwater in pollution field 100 leans locally alkaline.

  The inorganic carbonate concentration Z (mg / L) in the groundwater in the contaminated area 100 is measured before the start of one cycle, and an inorganic carbon amount X supplied to the contaminated area 100 is set. When supplying ozone gas and the sustaining body alternately, the ozone gas supply is stopped and the sustaining body is supplied to the groundwater. Here, a specific example in the cycle shown in FIG. 4 will be described in the case where inorganic carbonic acid is used as the sustaining body. The time for the step (T1) of supplying inorganic carbonic acid (sustained form) to the groundwater shown in FIG. 4 is 1 to 205 minutes, preferably 7 to 164 minutes.

  If the supply time of inorganic carbonic acid (sustained form) is less than 1 minute, sufficient time for supplying inorganic carbonic acid (sustained form) to groundwater cannot be secured. In addition, when the supply time of the inorganic carbonic acid (sustained form) is 205 minutes or longer, the time for stopping the supply of ozone gas becomes long, and the dissolved ozone concentration in the groundwater decreases. As a result, the time required for the purification of groundwater containing contaminants in the contaminated area 100 becomes longer. Also, the time of the step (T2) of supplying ozone gas to the ground water shown in FIG. 4 is 1 minute to 7200 minutes, preferably 30 minutes to 4320 minutes.

  When the supply time of ozone gas is less than 1 minute, the ozone supply rate is low, and the dissolved ozone concentration detected in the groundwater is low. When the supply time of the ozone gas is 7200 minutes or more, the concentration of inorganic carbonic acid (sustained substance) in the groundwater decreases due to sparging, and the effect of maintaining the dissolved ozone decreases. 3 and FIG. 4, even if the cycle is as shown in FIG. 3 and FIG. 4, for example, if the inorganic carbonate concentration in the groundwater in the contaminated area 100 is 20 mg / L or more, FIG. It is also conceivable that the step T1 is not performed. Even in this case, the second and subsequent cycles start from the step T1.

  This is because the concentration of inorganic carbonic acid (sustained substance) in groundwater is reduced by sparging, so that the dissolved ozone in the groundwater is sustained by replenishing the groundwater with inorganic carbonic acid (sustained substance) every predetermined time. It is. When the inorganic carbonic acid (sustained form) shown in FIG. 3 is continuously supplied, the inorganic carbonic acid (per unit time) supplied per unit time compared to the case where the inorganic carbonic acid (sustained form) shown in FIG. Set the amount of Persistent) small. Therefore, in any case where the inorganic carbonic acid (sustained body) is continuously supplied as shown in FIG. 3 or intermittently supplied as shown in FIG. Are equivalent. In addition, since the point regarding the cycle of FIG. 3 and FIG. 4 at the time of using an inorganic carbon as a persistence body is the same also in the case of persistence bodies other than the inorganic carbonate shown below, the description is abbreviate | omitted suitably. To do.

Next, the case where a monohydric alcohol is used as the sustaining body of the second supply unit 3 will be described. As the monohydric alcohol, either methanol, ethanol or butanol is used. Dissolved organic carbon (Dissolved Organic. Carbon, hereinafter referred to as “DOC”) concentration in groundwater in the contaminated area 100 is in the range of 0.1 mg / L to 5 mg / L, more preferably 0.5 mg / L to 2 mg / L. A monohydric alcohol is supplied to groundwater so that it may become L range. The reaction rate constant between the monohydric alcohol and the OH radical involved in the self-decomposition of dissolved ozone is as large as 10 ⁸ M ⁻¹ · s ⁻¹ to 10 ⁹ M ⁻¹ · s ⁻¹ . For this reason, the self-decomposition of dissolved ozone is suppressed and the dissolved ozone concentration can be sustained.

  When supplying monohydric alcohol, as in the case of supplying inorganic carbonic acid, the DOC concentration of the contaminated area 100 is measured every cycle or every predetermined time, and the supply amount XA (L) of monohydric alcohol is set. . When the average DOC concentration of groundwater is increased by 2 mg / L or more during the purification method as compared with the average DOC concentration S (mg / L) of the groundwater before the start of the purification treatment of the contaminated area 100, 1 of the second supply unit 3 The supply of monohydric alcohol is interrupted and only ozone gas is supplied. Thereby, monohydric alcohol can prevent excessive supply to the contaminated area 100.

  Next, the case where an acid solution is used as the sustaining body of the second supply unit 3 will be described. As the acid solution, an acid solution selected from sulfuric acid, hydrochloric acid or citric acid is supplied to the groundwater, so that the pH of the groundwater is reduced to a range of pH 3 to pH 6. When the pH of groundwater is 3 or less, the supply rate of the acid solution is high and the cost is high. Moreover, when the pH of groundwater is pH 6 or higher, the self-decomposition rate of dissolved ozone is large, and the dissolved ozone cannot be sustained in the groundwater. When the groundwater in the contaminated area 100 has a pH of 7 and a water temperature of 20 ° C., the dissolved ozone self-decomposition rate constant is reduced to about 1/5 by reducing the pH of the groundwater from pH 3 to pH 6. Thereby, the self-decomposition of the dissolved ozone dissolved in the groundwater is suppressed and sustained.

  When the acid solution is supplied, the pH of the groundwater in the contaminated area 100 is measured every cycle of the purification method or every predetermined time, as in the case of supplying the inorganic carbonic acid shown above, and the groundwater in the contaminated area 100 is measured. An acid solution is supplied to the ground water so that the pH is from pH 3 to pH 6. Even if the carbon dioxide gas shown above is supplied to the groundwater, the pH of the groundwater can be reduced, so that the same effect is produced.

  In the first embodiment, a method for supplying ozone gas to groundwater as a gas body is shown as an example. However, for example, ozone water in a state where ozone is dissolved in water may be injected into the groundwater. Or you may inject | pour into groundwater as the aqueous solution which mixed the continuous body and ozone. Since these are the same in the following embodiments, the description thereof will be omitted as appropriate.

  According to the purification device and the purification method of the first embodiment configured as described above, ozone gas is supplied to the ground water and a sustaining body that maintains dissolved ozone in the ground water is supplied. Thereby, the self-decomposition of dissolved ozone in groundwater can be suppressed. Therefore, it can reach | attain the position away from the position where ozone gas in soil passed as ozone water. As a result, the decomposition and removal of contaminants in the contaminated area proceeds.

  In the first embodiment, the first pipe 51 is not explicitly provided with a function, but the first pipe 51 connected to the first supply unit 2 is provided with means for preventing the backflow of ozone gas. May be. Moreover, you may provide the interruption | blocking means which interrupts | blocks the flow path of the 1st piping 51. FIG. When the blocking means is provided in this way, the supply of ozone gas may be controlled by connecting the control unit 4 and the blocking means. This can be similarly applied to other pipes, and also to the pipes in the following embodiments, which have the same functions and can be similarly performed.

Embodiment 2. FIG.
In Embodiment 2 of the present invention, a gas different from ozone gas is supplied to the groundwater in the soil in addition to the ozone gas and the sustaining body. Naturally, the gas different from the ozone gas is a gas that does not promote the self-decomposition of ozone, and it is conceivable to use air.

  FIG. 6 is a diagram showing a configuration of a purification device according to Embodiment 2 of the present invention. In the figure, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. A third supply unit 6 is connected to the well 1. The third supply unit 6 is configured by a blower or a compressor. Therefore, the third supply unit 6 can adjust the supply amount of air by adjusting the output of the blower or the compressor. The well 1 and the third supply unit 6 are connected by a third pipe 53. The third supply unit 6 supplies air as a gas different from ozone gas to the well 1. The control unit 4 adjusts the output of the blower or compressor as the third supply unit 6 via the third signal line 83 to control the supply of air.

  When the absolute pressure of the jet pressure of the third supply unit 6 may be less than 0.2 MPa, a blower or a compressor is used. Moreover, when 0.2 MPa or more is required, a compressor is used. When a compressor is used as the third supply unit 6, an oil-free type compressor, or an oil removal filter is installed at an ejection location of the compressor. Thereby, oil is removed in supply of the air of the 3rd supply part 6, and mixing of the oil to groundwater can be prevented. In the second embodiment, an example is shown in which air is used as the gas. However, the present invention is not limited to this, and any gas different from ozone gas can be used.

  Next, the purification method by the purification apparatus of Embodiment 2 configured as described above will be described based on the flowchart shown in FIG. In addition, since the supply method of ozone gas and a sustaining body is the same as that of the said Embodiment 1, the description is abbreviate | omitted. The control unit 4 controls the output of, for example, a blower or a compressor as the third supply unit 6 via the third signal line 83, and sets a desired air supply condition (step ST7 in FIG. 17). Next, the 3rd supply part 6 controlled by the control part 4 supplies air to the underground water of the contaminated area 100 from the ejection part 11 of the lower part of the well 1 via the 3rd piping 53 (as 3rd process). Step ST8 in FIG. Next, when air is supplied for a predetermined time, the control unit 4 controls the third supply unit 6 via the third signal line 83 to stop the supply of air (step ST9 in FIG. 17).

  In the second embodiment, as shown in FIG. 17, the step of supplying ozone gas to the ground water (first step), the step of supplying the sustaining body to the ground water (second step), and the air to the ground water It is only necessary to include a supplying step (third step), and various examples of the combination of the first step, the second step, and the third step, and the timing can be considered. Hereinafter, examples of combinations and timings of the first process, the second process, and the third process will be described with reference to FIGS. 7 and 8.

  Next, the supply timing and stop timing of the ozone gas, the sustaining body, and the air in the purification method in the case of using the air of the second embodiment described above are based on the timing chart examples of FIGS. 7 and 8. explain. 7 and 8 show a series of operations of the purification method according to the second embodiment of the present invention as one cycle.

  Specifically, one cycle is divided into an arbitrary number of steps T. Here, when one cycle is divided into three, it is set as T1 process, T2 process, and T3 process, respectively, and the presence or absence of supply of ozone gas, a sustaining body, and air is set in the operation of each process. Note that the division of one cycle may be set to an arbitrary number of three or more. The purification method in FIG. 7 supplies a sustaining body to the groundwater in the T1 step (second step), and does not supply ozone gas and air (stop). Next, in step T2, ozone gas and the sustaining body are simultaneously supplied to the groundwater (simultaneous step of the first step and the second step), and air is not supplied (stopped).

Next, in step T3, ozone gas, the sustaining body, and air are simultaneously supplied to the groundwater (simultaneous step of the first step, the second step, and the third step). When the operating conditions of the first supply unit 2 are constant in the T2 step and the T3 step, the gas flow rate is increased in the T3 step because ozone gas and air are mixed. Therefore, the concentration of ozone gas supplied to groundwater is reduced. For this reason, when the gas flow rate is increased by mixing air, the dissolved ozone concentration in the groundwater is maintained by supplying high-concentration ozone gas, for example, ozone gas having a concentration of 200 g / Nm ³ , to the groundwater. Further, since the amount of gas supplied to the groundwater per unit time increases, the soil pressure in the contaminated area 100 increases.

  As the soil pressure increases, the groundwater between the soil particles in which bubbles of sparged gas are difficult to pass is discharged from between the soil particles. Contaminants are eluted together with the discharged groundwater, and dissolved ozone and the eluted pollutants come into contact with the groundwater around these soils, so that the decomposition of the pollutants in the contaminated area 100 further proceeds. Moreover, after the end of the T3 step, the soil pressure is lowered, so that the groundwater is drawn between the particles of the soil where the bubbles are difficult to pass through or the soil where the groundwater is difficult to permeate. Dissolved ozone is present in the groundwater drawn between the soil particles, and pollutants contained in these soils are decomposed in contact with ozone gas. Therefore, when performing the purification | cleaning method which repeats 1 cycle, you may provide the period which does not inject | pour gas or a liquid after completion | finish of 1 cycle. Alternatively, in step T3, the supply amount of air may be supplied constantly, or the supply amount may be switched every predetermined time for operation.

  When the supply amount is switched in this manner, the change in the soil pressure in the contaminated area 100 becomes large in the T3 step, and ozone can reach the soil where ozone gas bubbles in the contaminated area 100 are difficult to pass as ozone water. Furthermore, the T3 step may be repeated after the T3 step. When repeating the T3 step, the second air flow rate may be larger or smaller than the first T3 step air flow rate. Thereby, the time for the soil pressure in the contaminated area 100 to change becomes longer, and dissolved ozone can reach the entire groundwater in the contaminated area 100.

  Moreover, the purification method in FIG. 8 supplies a sustaining body and air to the groundwater in the T1 step (simultaneous step of the second step and the third step), and does not supply ozone gas (stop). Next, in step T2, ozone gas is supplied to the groundwater (first step), and the sustaining body and air are not supplied (stop). Next, in step T3, ozone gas and air are simultaneously supplied to the groundwater (simultaneous step of the first step and the third step), and the sustaining body is not supplied (stop). In the T1 step, air and a sustaining body are supplied simultaneously. Thereby, the sustaining body can be diffused into the groundwater in the contaminated area 100 using the flow of air bubbles. In the T2 process, ozone gas is supplied to the groundwater. In the T3 process, the gas flow rate is increased by supplying ozone gas and air at the same time, and dissolved ozone easily spreads in the groundwater in the contaminated area 100. In the T3 step, similarly to the case shown in FIG. 7, the air supply amount may be supplied constantly, or the supply amount may be switched every predetermined time.

  The time of the air supply process shown in FIGS. 7 and 8 is equivalent to the time of the ozone gas supply process. That is, the air supply time is 1 minute to 7200 minutes, preferably 30 minutes to 4320 minutes. If the air supply time is less than 1 minute, the time during which the soil pressure in the contaminated area 100 increases is short, and ozone cannot reach the soil where bubbles are difficult to pass as ozone water. When the air supply time is 7200 minutes or longer, the time during which dissolved ozone in the groundwater is maintained at a low concentration becomes longer. As a result, the time for groundwater purification treatment becomes longer.

  Next, the case where the air supply amount is switched at predetermined intervals in the step T3 shown in FIGS. 7 and 8 will be described. In the T3 step, the air supply amount is increased from 0% to 100% at a constant speed. Alternatively, the air flow rate is changed from 1.1 times to 10 times, preferably from 1.5 times to 5 times the ozone gas flow rate at predetermined time intervals during the T3 step. If it is 1.1 times or less, the change in the soil pressure in the contaminated area 100 is small, and ozone water cannot reach the soil in which bubbles in the contaminated area 100 are difficult to pass.

  If it is 10 times or more, since the change in gas flow rate becomes large, the cost of the apparatus for making the pressure resistance specification high. When switching the air flow rate in the T3 step, at least once, after increasing the air flow rate, the air flow rate is decreased, or after the air flow rate is decreased, the air flow rate is increased. Thereby, the period when the soil pressure of the contaminated area 100 fluctuates can be provided at least once in one cycle.

  Next, the air supplied as described above will be described. First, the flow rate of the air in the third supply unit 6 is set to 1 L / min to 1000 L / min, preferably 10 L / min to 200 L / min. The air is supplied for diffusing dissolved ozone in the contaminated area 100. Therefore, if the flow rate of air is less than 1 L / min, it is not possible to assist in spreading dissolved ozone over the entire groundwater in the contaminated area 100 due to a shortage of air flow. When the flow rate of air is 1000 L / min or more, the energy consumption of the third supply unit 6 becomes large and the cost becomes high.

Next, the air ejection pressure of the third supply unit 6 is set to 0.1 MPa to 1.5 MPa as an absolute pressure, preferably 0.15 MPa to 1 MPa. If the air pressure is less than 0.1 MPa, the pressure is lower than the atmospheric pressure and cannot be efficiently supplied to the groundwater. On the other hand, when the air pressure is 1.5 MPa or more, the power consumption is increased, and the apparatus is further increased in size and cost. When air is mixed with ozone gas and supplied to groundwater as a mixed gas, the flow rate of air is made larger than the flow rate of ozone gas. For example, when ozone gas having a concentration of 200 g / Nm ³ is supplied to groundwater, the ozone gas concentration decreases by mixing with air, but if the amount of ozone supplied to groundwater does not change during a predetermined time, dissolved ozone in groundwater Can be sustained.

  According to the purification device and the purification method of the second embodiment configured as described above, the same effect as that of the first embodiment can be obtained, and the third supply unit that supplies air can be provided. In addition, the fluctuation range of pressure in the contaminated area in the soil increases. As a result, the penetration of dissolved ozone into the contaminated area in the soil and the discharge of the pollutants are promoted, and the degradation rate of the pollutants is improved.

  Moreover, since air is used as the third supply unit, the cost is low.

Embodiment 3 FIG.
In Embodiment 3 of the present invention, in addition to ozone gas, a sustaining body, and air, a heating fluid is supplied to groundwater in the soil. It is conceivable to use steam (water vapor) as the heating fluid.

  FIG. 9 is a diagram showing a configuration of a purification device according to Embodiment 3 of the present invention. In the figure, the same parts as those in the above embodiments are denoted by the same reference numerals, and description thereof is omitted. A fourth supply unit 7 is connected to the well 1. The well 1 and the fourth supply unit 7 are connected by a fourth pipe 54. The fourth supply unit 7 supplies the well 1 with steam created with water as a heating fluid. The 4th supply part 7 is comprised with a steam generator. Therefore, the fourth supply unit 7 can adjust the supply amount of steam by adjusting the output of the steam generator. The control unit 4 controls the supply of steam from the fourth supply unit 7 via the fourth signal line 84. In the third embodiment, steam is used as the heating fluid. However, the present invention is not limited to this, and any other substance can be used as long as it is a heating fluid.

  Next, a purification method by the purification apparatus of the third embodiment configured as described above will be described based on the flowchart shown in FIG. In addition, since the supply method of ozone gas, a sustaining body, and air is the same as that of the said Embodiment 2, the description is abbreviate | omitted. The control unit 4 controls the output of, for example, a steam generator as the fourth supply unit 7 via the fourth signal line 84, and sets a desired steam supply condition (step ST10 in FIG. 18). Next, the 4th supply part 7 controlled by the control part 4 supplies steam into the ground water of the contaminated area 100 from the ejection part 11 of the lower part of the well 1 via the 4th piping 54 (as a 4th process). Step ST11 in FIG. 18). Next, when steam is supplied for a predetermined time, the control unit 4 controls the fourth supply unit 7 via the fourth signal line 84 and stops the supply of steam (step ST12 in FIG. 18).

  In this Embodiment 3, as shown in FIG. 18, the process (1st process) which supplies ozone gas to groundwater, the process (2nd process) which supplies a sustaining body to groundwater, and air to groundwater It is only necessary to have a step of supplying (third step) and a step of supplying steam to the ground water (fourth step), a combination of the first step, the second step, the third step and the fourth step, and There are various examples of timing. However, since the dissolved ozone promotes self-decomposition as the temperature rises, the supply of steam is not performed simultaneously with the supply of ozone gas. Hereinafter, examples of combinations and timings of the first process, the second process, the third process, and the fourth process will be described with reference to FIGS. 10 to 12.

  The supply and stop timings of ozone gas, sustaining body, air, and steam in the purification method using the steam of the third embodiment shown above will be described based on the timing chart examples of FIGS. 10 to 12. To do. First, FIGS. 10 to 12 show a series of operations of the purification method according to the third embodiment of the present invention as one cycle.

  Specifically, one cycle is divided into an arbitrary number of steps T. Here, when one cycle is divided into 5 or 4 parts, T1 process, T2 process, T3 process, T4 process, and T5 process are used, respectively, and whether or not ozone gas, sustainer, air, and steam are supplied in the operation of each process Set. The purification method in FIG. 10 supplies the sustaining body to the groundwater in the T1 step (second step), and does not supply ozone gas, air, and steam (stop). Next, in step T2, ozone gas and the sustaining body are simultaneously supplied to the groundwater (simultaneous process of the first process and the second process), and air and steam are not supplied (stop).

  Next, in T3 process, ozone gas, a sustaining body, and air are simultaneously supplied to groundwater (simultaneous process of the 1st process, the 2nd process, and the 3rd process), and steam is not supplied (stop). Next, in step T4, ozone gas, the sustaining body, and air are simultaneously supplied to the groundwater (simultaneous step of the first step, the second step, and the third step), and steam is not supplied (stopped). The T3 process and the T4 process have different air flow rates. Next, in step T5, steam is supplied to the groundwater (fourth step), and ozone gas, the sustaining body, and air are not supplied (stop).

  Further, in the purification method in FIG. 11, in the T1 step, the sustaining body and steam are simultaneously supplied to the ground water (simultaneous step of the second step and the fourth step), and ozone gas and air are not supplied (stopped). Next, in step T2, ozone gas and the sustaining body are simultaneously supplied to the groundwater (simultaneous process of the first process and the second process), and air and steam are not supplied (stop). Next, in T3 process, ozone gas, a sustaining body, and air are simultaneously supplied to groundwater (simultaneous process of the 1st process, the 2nd process, and the 3rd process), and steam is not supplied (stop). Next, in step T4, ozone gas, the sustaining body, and air are simultaneously supplied to the groundwater (simultaneous step of the first step, the second step, and the third step), and steam is not supplied (stopped). The T3 process and the T4 process have different air flow rates. As described above, when the sustaining body and the steam are simultaneously supplied in the T1 step, the persistence body is heated by the steam, so that the viscosity of the fluid is lowered and the permeation into the soil of the contaminated region 100 is facilitated.

  Moreover, the purification method in FIG. 12 supplies a sustaining body to groundwater (2nd process) in a T1 process, and does not supply ozone gas, air, and steam (stop). Next, in step T2, ozone gas and the sustaining body are simultaneously supplied to the groundwater (simultaneous process of the first process and the second process), and air and steam are not supplied (stop). Next, in T3 process, ozone gas, a sustaining body, and air are simultaneously supplied to groundwater (simultaneous process of the 1st process, the 2nd process, and the 3rd process), and steam is not supplied (stop). Next, in step T4, ozone gas, the sustaining body, and air are simultaneously supplied to the groundwater (simultaneous step of the first step, the second step, and the third step), and steam is not supplied (stopped). The T3 process and the T4 process have different air flow rates.

  Next, in step T5, air, a sustaining body, and steam are simultaneously supplied to the groundwater (simultaneous step of the second step, the third step, and the fourth step), and ozone gas is not supplied (stop). Thus, if air, a continuation body, and steam are simultaneously supplied to groundwater at T5 process, a continuation body and air will be heated by steam. The air bubbles and the sustaining body heated by the steam rise in the soil in the contaminated area 100, so that a wider range of soil can be heated and infiltrated.

  10 to 12, the flow rate of air in the T3 process and the T4 process may be larger, and the gas flow rate in the process having a larger flow rate than in the process having a smaller flow rate is 1.1 to 10 times, preferably 1 .5 to 5 times. When the flow rate ratio is 1.1 times or less, the change in the soil pressure in the contaminated area 100 is small, and ozone water cannot reach the soil in which bubbles in the contaminated area 100 are difficult to pass. If the flow rate ratio is 10 times or more, the fluctuation range becomes too large, and it is necessary to make the apparatus have a pressure resistance specification, resulting in high cost.

  In addition, by supplying steam or a mixed gas of steam and air into the groundwater, the temperature of the groundwater in the contaminated area 100 increases, the viscosity of the groundwater decreases, and the groundwater easily penetrates into the soil. . In addition, when the soil in which the groundwater in the contaminated area 100 is difficult to permeate is heated, the pollutants contained in these soils are eluted into the groundwater, so that there is an opportunity for the dissolved ozone in the groundwater to come into contact with the pollutants. improves. Therefore, the decomposition rate of the contaminant in the contaminated area 100 is improved.

  When mixing with the steam supplied from the fourth supply unit 7 and the air supplied from the third supply unit 6, the temperature is set to 20 ° C to 150 ° C, preferably 30 ° C to 100 ° C. When these temperatures are 20 ° C. or lower, the effect of supplying steam cannot be obtained because it is equivalent to a general groundwater temperature of 18 ° C. Moreover, if these temperatures are 150 degreeC or more, it is necessary to make the heat resistance of a piping member high, and it becomes high cost.

  According to the purification device and the purification method of the third embodiment configured as described above, the fourth supply unit that supplies steam is provided as well as the same effects as those of the above-described embodiments. Therefore, it is possible to elute the pollutants contained in the soil in which the groundwater in the contaminated area is difficult to permeate into the soil in which the groundwater easily permeates. Thereby, the pollutant contained in the groundwater in the soil in which the groundwater in the contaminated area is difficult to permeate can be decomposed and removed.

  Moreover, since the supply of ozone gas and the supply of steam are performed in different time zones, the effect of ozone gas is prevented from being reduced.

  Moreover, since steam is used as the fourth supply unit, the cost is low.

Embodiment 4 FIG.
In Embodiment 4 of the present invention, in addition to the ozone gas and the sustaining body, a mechanism for measuring the ozone gas concentration in the sucked gas in the soil and controlling the ozone injection rate into the groundwater is provided.

  FIG. 19 is a diagram showing a configuration of a purification device according to Embodiment 4 of the present invention. In the figure, the same parts as those in the above embodiments are denoted by the same reference numerals, and description thereof is omitted. A suction well 8 is provided as a suction part for sucking gas in the soil of the contaminated area 100 and inserted in the soil of the contaminated area 100. Here, the suction well 8 formed in the soil of the contaminated area 100 is shown as an example. However, the present invention is not limited to this, and as a suction unit for sucking the gas in the soil of the contaminated area 100, for example, A cover may be installed on the ground surface around the well 1 on the contaminated area 100 to serve as a suction unit for sucking gas in the soil of the contaminated area 100 instead of the suction well 8, or both of them may be installed. It is good also as a structure.

  A fifth pipe 55 is connected to the suction well 8. A gas-liquid separator 9, an exhaust gas treatment unit 10, and a suction blower 110 are sequentially connected to the fifth pipe 55. A sixth pipe 56 is further connected to the gas-liquid separator 9. A dehumidifying unit 12, an ozone gas monitor 130 as a measuring unit, and an exhaust gas processing unit 10 are connected to the sixth pipe 56 in this order. The ozone gas monitor 130 is connected to the control unit 4 via the fifth signal line 85 and transmits the measurement result to the control unit 4. The suction blower 110 is connected to the control unit 4 via the sixth signal line 86 and is controlled by the control unit 4. Specifically, the control unit 4 controls the suction start timing of the suction blower 110 and the operation of the suction gas flow rate.

  The gas / liquid separation unit 9 separates the gas / liquid of the gas sucked from the suction well 8 and takes out only the gas. The dehumidifying unit 12 acquires a part of the gas separated by the gas-liquid separating unit 9, that is, an amount of gas necessary for measuring the ozone gas concentration, and dehumidifies the gas. The ozone gas monitor 130 measures the ozone gas concentration in the gas dehumidified by the dehumidifying unit 12 and transmits the measurement result to the control unit 4. Further, the gas whose measurement has been completed is discharged to the exhaust gas treatment unit 10.

  The exhaust gas treatment unit 10 acquires a part of the gas separated by the gas-liquid separation unit 9, that is, a gas that has not been used to measure the ozone gas concentration and a gas that has been measured, and performs the exhaust gas treatment. Do. The suction blower 110 is a blower as a suction unit for sucking gas from the suction well 8 through the fifth pipe 55, and further discharges the gas exhausted in the exhaust gas processing unit 10 to the atmosphere. Based on the ozone gas concentration measured by the ozone gas monitor 130, the control unit 4 includes at least one of the first supply unit 2, the second supply unit 3, the third supply unit 6, the fourth supply unit 7, or the suction blower 110. Control one of them.

  Next, a purification method of the purification device of the fourth embodiment configured as described above will be described. In addition, since the supply method of ozone gas, a sustaining body, air, and steam is the same as that of each said embodiment, the description is abbreviate | omitted suitably. When ozone gas is injected into the groundwater in the contaminated area 100 from the well 1, the ozone gas is diffused into the groundwater in the soil. The ozone gas injected into the soil moves in the groundwater as bubbles in the groundwater and reaches the surface of the groundwater in the soil. In the soil from the groundwater surface to the ground surface, the gas in the soil moves through the pores of the soil particles. And the gas in the said soil is attracted | sucked from the suction well 8 using the suction blower 110 (suction process), and discharge | emission of the gas inject | poured into the groundwater in soil is accelerated | stimulated to the ground. Then, the gas is introduced into the gas-liquid separator 9 through the suction well 8 and the fifth pipe 55.

  Next, the gas in the soil recovered from the suction well 8 includes ozone gas that has not been dissolved by being injected into the ground water, and VOC that is vaporized from the VOC in the ground water and taken into the bubbles. The collected gas in the soil is separated into groundwater and gas by the gas-liquid separation unit 9, and the groundwater is removed. Next, of the gas in the soil separated by the gas-liquid separation unit 9, a gas that is not used for measuring the ozone gas concentration is introduced into the exhaust gas treatment unit 10. Then, the exhaust gas treatment unit 10 removes ozone, VOC, and the like from the gas, and the exhaust gas treatment is performed. The gas in the soil from which VOC and ozone have been removed and the exhaust gas treatment has been performed is released to the atmosphere through the suction blower 110.

  On the other hand, the gas in the soil for measuring the ozone gas concentration is introduced into the dehumidifying unit 12 to remove water vapor from the gas in the soil separated by the gas-liquid separation unit 9. Next, the ozone gas concentration contained in the gas in the soil dehumidified by the ozone gas monitor 130 is measured. Since water vapor is removed, dew condensation on the ozone gas monitor 130 can be prevented, and the ozone gas concentration can be accurately measured. In the measurement of the ozone gas concentration, not all the gas in the soil acquired in the suction well 8 is used, but only a part of the gas in the soil acquired in the suction well 8 is measured. In this way, since the amount of gas to be dehumidified is small compared to the case of measuring the entire gas sucked from the soil, energy consumption can be reduced. The result of the ozone gas concentration measured by the ozone gas monitor 130 is transmitted to the control unit 4 via the fifth signal line 85.

  Based on the obtained measurement result of the ozone gas concentration, the control unit 4 makes the first supply unit 2, the second supply unit 3, and the third supply unit so that the ozone gas concentration becomes a predetermined value obtained in advance as a purification device. 6, a signal is transmitted to any one or all of the fourth supply unit 7 and the suction blower 110, and the concentration of ozone gas injected into the groundwater in the soil, the flow rate of ozone gas, the amount of injected sustaining body, The timing of switching or the gas flow rate sucked in the suction well 8, that is, the suction blower 110 is controlled.

  An example of a specific method for controlling the suction blower 110 in the control unit 4 will be described. The suction gas flow rate of the suction blower 110 controlled by the control unit 4 is set to 0.5 to 10 times, preferably 1 to 5 times the injection gas flow rate of the ozone gas supplied from the first supply unit 2. . By setting the suction gas flow rate to be larger than the injection gas flow rate, the discharge of the gas injected into the groundwater in the soil is promoted. As a result, VOC decomposition and removal in the contaminated area 100 is promoted.

  FIG. 20 is a schematic diagram schematically showing an example of a change with time of the ozone gas concentration contained in the gas in the sucked soil measured by the ozone gas monitor 130. As shown in the figure, after the start of ozone gas injection into the groundwater in the soil, the concentration of ozone gas contained in the gas in the soil increases and stabilizes over time. In the control part 4, based on the change in the ozone gas concentration contained in the gas in the soil, the concentration of the ozone gas injected into the groundwater in the soil, the flow rate of the ozone gas, the injection amount of the sustaining body, the switching timing of each process or The flow rate of gas sucked in the suction well 8, that is, the suction blower 110 is controlled so that the concentration of ozone gas becomes a predetermined value.

  Alternatively, the soil pressure around the suction well 8 may be changed by controlling the suction blower 110 to change the flow rate of the gas sucked from the suction well 8. Varying the soil pressure around the suction well 8 can increase the chance of contact between the VOC and ozone at a location where ozone gas or ozone water is difficult to penetrate, increasing the possibility of VOC decomposition and removal.

  According to the purification device and the purification method of the fourth embodiment configured as described above, the same effects as those of the above-described embodiments can be obtained, and ozone more than necessary for the VOC decomposition is groundwater in the soil. The running cost can be reduced.

  According to the purification device and the purification method of the fourth embodiment configured as described above, the suction unit that sucks gas from the soil, as well as the same effects as those of the above embodiments, and the suction And a control unit that measures the ozone gas concentration of the ozonized oxygen gas from the gas sucked by the unit, and the control unit is configured based on the ozone gas concentration measured by the measurement unit, the first supply unit, the second supply unit Since at least one of the third supply unit, the fourth supply unit, and the suction unit is controlled, the supply amount of ozone gas can be appropriately controlled in the purification.

  The configuration of the purification device of the fourth embodiment may be other than that shown in FIG. 19. For example, one and the other of the sixth pipe 56 are connected from the gas-liquid separation unit 9 to the exhaust gas treatment unit 10. You may branch and install in the 5th piping 55 in between. Alternatively, one or the other of the dehumidifying unit 12, the ozone gas monitor 130, and the sixth pipe 56 may be connected to the gas-liquid separation unit 9 and the ozone gas concentration inside the gas-liquid separation unit 9 may be measured. In that case, a suction pump for taking gas into the dehumidifying unit 12 is installed in the sixth pipe 56. However, when the ozone gas monitor 130 is a gas self-priming type, it is not necessary to install a suction pump.

  In each of the above-described embodiments, the description has focused on the purification method for one cycle. However, when the purification method is performed by repeating one cycle, the time period during which all the processes are stopped after the completion of one cycle. May be set, and after that time, the purification method may be performed by implementing one cycle again. Further, in each of the above-described embodiments, the purification method in which any one of the steps is performed in the one-cycle purification method has been mainly described. However, the present invention is not limited to this, and in each cycle, It is also possible to set a time zone during which all of the supply of the process is stopped, and then appropriately perform each process.

  In this way, if all the supply to the soil is stopped, the soil pressure is reduced. Therefore, the soil gap that has been narrowed by the large soil pressure becomes wider. As a result, groundwater that has come into contact with ozone and groundwater that has not come into contact with ozone are mixed, and VOC and ozone at places where gas purging is difficult or where ozone water is difficult to penetrate can come into contact with ozone. The possibility of removal increases.

  The purification devices shown in the first to fourth embodiments are only examples, and are not limited to these configurations. Even if the purification devices have other configurations, the first step to the fourth step. As long as the purification device can appropriately perform the suction process and the like, the same purification method can be performed and the same effect can be obtained. Moreover, although the example which controls all of the 1st supply part 2, the 2nd supply part 3, the 3rd supply part 6, the 4th supply part 7, and the suction blower 110 with one control part 4 was shown, There is no limitation, and each of the first supply unit 2, the second supply unit 3, the third supply unit 6, the fourth supply unit 7, and the suction blower 110 may be provided with a control unit. However, the first supply unit 2, the second supply unit 3, the third supply unit 6, the fourth supply unit 7, and the suction blower 110 are controlled in association with each other so that the purification method of each of the above embodiments is possible. .

  Next, the effect of the invention in the sustaining body in the purification device and the purification method of the first to fourth embodiments and the air supply of the second embodiment will be verified. An explanation will be given based on the results of an experiment in which a VOC treatment as a pollutant by supplying ozone gas was performed using the lab-scale purification apparatus shown in FIG. In the figure, the same parts as those in the above embodiments are denoted by the same reference numerals, and the description thereof is omitted. As the contaminated area 100, a lab-scale reaction tank 13 in which sand 16 containing simulated contaminated groundwater adjusted in an experiment is enclosed is used.

  A supply hole 14 is formed in the lower part of the reaction tank 13, and ozone gas is supplied from the first supply unit 2, a sustaining body is supplied from the second supply unit 3, and air is supplied from the third supply unit 6 through the respective pipes 51, 52, 53. Is done. A discharge hole 15 is formed in the upper part of the reaction tank 13, and ozone gas is discharged to the first supply unit 2 through the discharge pipe 21. The discharged ozone gas returns to oxygen gas in the exhaust ozone gas decomposition tower of the first supply unit 2. The reaction tank 13 includes a plurality of water sampling positions 171, 172, 173, 174, 175 at different positions.

Example 1.
In the experiments of Example 1 and Comparative Example 1, simulated contaminated groundwater in which VOC as a contaminant was added to pure water so as to have a concentration of 10 mg / L was used. FIG. 14 shows the conditions of the experiment using the laboratory-scale reaction tank 13 shown in FIG. The case where sodium hydrogen carbonate (sustained form) is added to the simulated contaminated groundwater as inorganic carbonate is shown as Example 1, and the case where sodium bicarbonate is not added is shown as Comparative Example 1. And after completion | finish of processing time, all the water in the reaction tank 13 was collect | recovered, and the VOC removal effect by ozone gas supply was compared. As a result, the VOC removal rate of Example 1 to which inorganic carbonate was added was 98%. On the other hand, the VOC removal rate of Comparative Example 1 was 70%. By adding inorganic carbonic acid to the simulated contaminated groundwater, it was confirmed that the VOC removal rate was improved when inorganic carbonic acid was added than when treated with ozone gas alone. In addition, although the example which used VOC as a pollutant was shown, it can be estimated that another pollutant has the same effect. This also applies to the following embodiments.

Example 2
In the experiments of Example 2 and Comparative Example 2, simulated contaminated groundwater in which VOC was added to river water so as to have a concentration of 5 mg / L was used. FIG. 15 shows the experimental conditions using the laboratory-scale reaction tank 13 shown in FIG. In Example 2, a mixed gas of ozone gas and air was supplied to the simulated contaminated groundwater in Comparative Example 2, and the dissolved ozone concentration in the simulated contaminated groundwater was measured. Simulated contaminated groundwater was sampled from the sampling positions 171, 172, 173, 174 and 175 of the reaction tank 13. The results show that, as in Example 2 in FIG. 15, the dissolved ozone concentration of the treated water when air is mixed with ozone gas in the reaction tank 13 and supplied for 60 minutes is 0.7 mg at the sampling positions 174 and 175, respectively. / L, 0.3 mg / L.

  Moreover, the dissolved ozone concentration of the treated water when supplying ozone gas to the reaction tank 13 for 60 minutes as in Comparative Example 2 was 1.1 mg / L and 0.0 mg / L at the sampling positions 174 and 175, respectively. . When air mixed with ozone gas was supplied to the simulated contaminated groundwater, dissolved ozone was detected even at a position away from the supply hole 14, and the detectable range of dissolved ozone was expanded.

Example 3
Next, the effect of the invention in the supply of steam in the purification device and the purification method of the third embodiment will be verified. In the experiments of Example 3 and Comparative Example 3, 50 mL of sand and 70 mL of pure water were filled in a 150 mL glass container, and 2 mg of VOC was supplied to the sand bottom in the glass container using a syringe. This glass container was stored for a predetermined time at a water temperature of 18 ° C. as Comparative Example 3 and at 80 ° C. corresponding to the state where steam was supplied as Example 3, and the VOC concentration of water in the glass container was measured. The results show that at a water temperature of 18 ° C. in Comparative Example 3 or at a water temperature of 80 ° C. in Example 3, the VOC elution rate per unit time is 0.5 μg / hr or 98 μg / hr, respectively, and the groundwater is heated. As a result, VOC eluted into the groundwater around the soil.

  It should be noted that the present invention can be freely combined with each other within the scope of the invention, and each embodiment can be appropriately modified or omitted.

1 well, 11 ejection section, 2 first supply section, 3 second supply section, 4 control section,
6 3rd supply part, 7 4th supply part, 21 discharge pipe, 51 1st piping, 52 2nd piping,
53 3rd piping, 54 4th piping, 81 1st signal line, 82 2nd signal line,
83 Third signal line, 84 Fourth signal line, 13 reaction tank, 14 supply hole, 15 discharge hole,
16 Sand, 171 sampling position, 172 sampling position, 173 sampling position,
174 sampling location, 175 sampling location, 100 contaminated area, 8 suction wells,
9 Gas-liquid separator, 12 Dehumidifier, 110 Suction blower, 130 Ozone gas monitor,
55 fifth pipe, 56 sixth pipe, 85 fifth signal line, 86 sixth signal line.

Claims (23)

In a purification device that purifies groundwater in the soil,
A sparging well inserted into the soil;
A first supply unit for supplying ozone to the sparging well;
A second supply section for supplying a sustaining body that suppresses decomposition of ozone to the sparging well;
A purification device comprising: a control unit that controls the first supply unit and the second supply unit. The said control part is a purification apparatus of Claim 1 which performs control which starts supply of the said ozone by a said 1st supply part, after the said 2nd supply part starts supply of the said sustaining body. A suction part for sucking gas from the soil;
A measurement unit for measuring the ozone gas concentration of the gas sucked in the suction unit,
The said control part controls at least any one of said 1st supply part, said 2nd supply part, or said suction part based on the ozone gas density | concentration measured in the said measurement part. 2. The purification apparatus according to 2. The purification device according to any one of claims 1 to 3, wherein the sustaining body includes at least one of inorganic carbonic acid, carbon dioxide gas, monohydric alcohol, and an acid solution. The purification apparatus of any one of Claims 1-4 provided with the 3rd supply part which supplies the gas different from ozonized oxygen gas to the said sparging well. The said control part controls supply of the said gas of a said 3rd supply part, and controls so that the flow volume of the said gas of a said 3rd supply part becomes larger than the supply flow rate of ozone of a said 1st supply part. 5. The purification device according to 5. The purification apparatus according to claim 5 or 6, wherein the gas is air. A suction part for sucking gas from the soil;
A measurement unit for measuring the ozone gas concentration of the gas sucked in the suction unit,
The control unit controls at least one of the first supply unit, the second supply unit, the third supply unit, and the suction unit based on the ozone gas concentration measured by the measurement unit. The purification device according to any one of claims 5 to 7. A fourth supply part for supplying a heating fluid to the sparging well;
9. The control unit according to claim 1, wherein the control unit controls the heating fluid supply of the fourth supply unit and the ozone supply of the first supply unit to be in different time zones. The purification device according to 1. A suction part for sucking gas from the soil;
A measurement unit for measuring the ozone gas concentration of the gas sucked in the suction unit,
The control unit controls at least one of the first supply unit, the second supply unit, the fourth supply unit, and the suction unit based on an ozone gas concentration measured by the measurement unit. 9. The purification device according to 9. In purification method to purify groundwater in soil,
A first step of supplying ozone to the groundwater;
And a second step of supplying a sustaining body that suppresses decomposition of ozone to the groundwater. Performing the first step and the second step simultaneously,
Or the purification method of Claim 11 which implements said 1st process and said 2nd process in a different time slot | zone. The purification method according to claim 11 or 12, wherein a time zone for stopping the first step and the second step is provided. At least one of the first step and the second step is:
The purification method according to any one of claims 11 to 13, wherein a supply amount supplied per unit time is varied. A suction step for sucking gas from the soil;
And a control step of controlling at least one of the first step, the second step, and the suction step based on an ozone gas concentration contained in the gas sucked in the suction step. The purification method according to any one of claims 11 to 14. Comprising a third step of supplying a gas different from the ozonized oxygen gas to the groundwater,
The purification method according to any one of claims 11 to 15, wherein the gas flow rate in the third step is supplied so as to be larger than the flow rate of the ozonized oxygen gas in the first step. A suction step for sucking gas from the soil;
A control step of controlling at least one of the first step, the second step, the third step and the suction step based on the ozone gas concentration contained in the gas sucked in the suction step. The purification method according to claim 16 provided. The purification method according to claim 16 or 17, wherein a time zone for stopping the first step, the second step, and the third step is provided. At least one of the first step, the second step, and the third step is:
The purification method according to any one of claims 16 to 18, wherein a supply amount supplied per unit time is varied. A fourth step of supplying a heated fluid to the groundwater,
The purification method according to any one of claims 11 to 19, wherein the first step and the fourth step are performed in different time zones. A suction step for sucking gas from the soil;
A control step of controlling at least one of the first step, the second step, the fourth step, and the suction step based on the ozone gas concentration contained in the gas sucked in the suction step. The purification method according to claim 20 provided. The purification method according to claim 20 or 21, wherein a time zone for stopping the first step, the second step, and the fourth step is provided. At least one of the first step, the second step, and the fourth step is:
The purification method according to any one of claims 20 to 22, wherein a supply amount supplied per unit time is varied.

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