JP2018035613A - Injection method for injection liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection method that inhibits clogging from occurring in an inlet of an injection well and ground on its periphery, when an injection liquid, to which an activator is added, is injected into the ground from the injection well.SOLUTION: In an injection method for an injection liquid, the injection liquid 30, to which an activator for activating decomposition microorganisms for decomposing contaminants in ground 12 is added, is injected into the ground 12 from an injection well 20. The addition of the activator to the injection liquid 30 is temporarily stopped.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an injection solution injection method.

  A water injection device that injects groundwater pumped from the ground into the ground from a water injection well. To prevent clogging of the water injection well, an oxidant is added to the groundwater injected into the ground to cause clogging. A water injection apparatus for sterilizing microorganisms therein is known (for example, see Patent Document 1).

  Moreover, in order to prevent clogging of a water injection well, the method of adding surfactant to the water injection poured into a ground from a water injection well is known (for example, refer patent document 1).

JP-A-9-131585 JP2015-004255A

  By the way, as a purification method for contaminated soil, for example, an injection solution to which an active agent (nutrient) such as a hydrogen sustained-release agent or a yeast extract is added is injected into the contaminated soil, and the pollutants in the contaminated soil are decomposed. There is known a biomethod (biostimulation) in which microorganisms (hereinafter referred to as “decomposing microorganisms”) are grown and activated to promote purification of contaminants by the decomposing microorganisms.

  In such a biomethod, microorganisms (microorganisms other than decomposing microorganisms) present in the injection solution or contaminated soil consumes (decomposes) the active agent in the injection solution, resulting in products of the injection well. Biofilms that cause clogging are likely to occur at the inlet and the surrounding ground. As a result, the injection efficiency of the injection liquid from the injection well to the ground may be reduced.

  In view of the above facts, the present invention aims to suppress clogging occurring at the inlet of the injection well and the surrounding ground when the injection liquid to which the activator is added is injected from the injection well into the ground. And

  The method for injecting an injection liquid according to claim 1 is an injection method in which an injection liquid to which an activator for activating decomposing microorganisms that decompose pollutants in the ground is added is injected from an injection well into the ground. Temporarily stopping the addition of the activator or temporarily reducing the amount of the activator added, adding the acidic additive to the infusion, heating the infusion, and disinfecting the infusion Adding at least one of the following steps.

  According to the method for injecting an infusion according to claim 1, for example, in one step, the addition of the activator to the infusion is temporarily stopped or the amount of the activator added is temporarily reduced. That is, the active agent in the injection solution that causes biofilm generation is eliminated, or the amount of active agent added is reduced. Thereby, it is suppressed that the biofilm which becomes a cause of clogging generate | occur | produces in the injection hole (screen part etc.) of an injection well, and its surrounding ground.

  In addition, with the decrease in the active agent in the injection solution, the biofilm present at the injection well and its surrounding ground is decomposed by itself or by microorganisms (microorganisms other than decomposing microorganisms).

  Furthermore, by injecting into the ground from the injection port of the injection well the injection liquid in which the active agent is not added or in which the addition amount of the active agent is reduced, the biofilm which has been decomposed and reduced can be washed away. Thereby, clogging of the injection port of the injection well and the surrounding ground is suppressed.

  Next, in another step, an acidic additive such as sodium hydroxide is added to the injection solution to make the injection solution acidic, or the degree of acidity is increased (for example, pH 8 or more). Thereby, it becomes easy to peel a biofilm from the injection hole of an injection well, or its surrounding ground. Therefore, clogging of the injection port of the injection well is suppressed.

  Next, in another process, the injection solution is heated (for example, 35 degrees or more). This suppresses the growth of microorganisms that cause biofilm generation. Therefore, clogging of the injection port of the injection well is suppressed.

  Next, in another step, a bactericide such as sodium hypochlorite is added to the injection solution. Thereby, the biofilm generated in the injection port of the injection well and the surrounding ground is easily destroyed (disinfected). Therefore, clogging of the injection port of the injection well is suppressed.

  According to a second aspect of the present invention, there is provided a method for injecting an injection liquid according to the first aspect, wherein at least one of the plurality of steps is periodically performed.

  According to the injection method of the injection liquid according to claim 2, at least one of the plurality of processes according to claim 1 is periodically performed. Thereby, clogging of the injection port of the injection well is suppressed. Therefore, the injection solution can be continuously injected from the injection well into the ground.

  An injection solution injection method according to claim 3 is the injection solution injection method according to claim 1 or 2, wherein at least one of the plurality of steps is performed by adding the injection solution in the injection well. This is performed when the liquid level is a predetermined value or more.

  According to the method for injecting an injection liquid according to claim 3, at least one of the plurality of processes according to claim 1 is performed with a liquid level of the injection liquid in the injection well (the height of the liquid surface of the injection liquid) being predetermined. Perform when the value is greater than or equal to.

  Here, when clogging occurs in the injection port of the injection well or the surrounding ground, the injection liquid injected from the injection well into the ground decreases, and the liquid level of the injection liquid in the injection well increases. By estimating the clogging of the inlet of the injection well and the surrounding ground based on the liquid level of the injection liquid, the clogging of the inlet of the injection well can be effectively eliminated.

  As described above, according to the method for injecting an injection solution according to the present invention, when an injection solution to which an activator is added is injected from the injection well into the ground, it occurs at the inlet of the injection well and the surrounding ground. Clogging can be suppressed.

It is a longitudinal section showing the ground where the underground soil purification system concerning one embodiment was applied. It is an expanded sectional view which shows the water injection well shown by FIG. 1, and the surrounding ground of the circumference | surroundings. It is a graph which shows the relationship between the addition period of the activator with respect to a water injection liquid, and the liquid level of the water injection liquid in a water injection well. It is a graph which shows the relationship between the addition period of the activator with respect to a water injection liquid, and the liquid level of the water injection liquid in a water injection well. It is a graph which shows the relationship between the addition period of the activator with respect to a water injection liquid, and the liquid level of the water injection liquid in a water injection well. It is a graph which shows the relationship between the addition period of the activator with respect to a water injection liquid, and the liquid level of the water injection liquid in a water injection well. It is a graph which shows the relationship between the addition period of the activator with respect to a water injection liquid, and the liquid level of the water injection liquid in a water injection well.

  Hereinafter, a method for injecting an injection solution according to an embodiment will be described with reference to the drawings.

(Underground soil purification system)
First, the underground soil purification system 10 which concerns on this embodiment is demonstrated.

  FIG. 1 shows an example of the ground 12 to which the underground soil purification system 10 according to the present embodiment is applied. The ground 12 has a hardly permeable layer 12A and an aquifer 12B deposited on the hardly permeable layer 12A. In addition, the code | symbol S shown by FIG. 1 has shown the groundwater level of the aquifer 12B. Moreover, the arrow V shown by FIG. 1 has shown the flow of groundwater.

  The aquifer 12B has higher water permeability than the poorly permeable layer 12A, and the groundwater easily flows. The aquifer 12B has a contaminated soil 12B1 containing a contaminant such as VOC (volatile organic compound).

  Contaminants include, for example, organic compounds (toluene, xylene, tetrachloroethylene, trichloroethylene, cis-1,2-dichloroethylene, chloroethylene (vinyl chloride) contained in paints, printing inks, adhesives, cleaning agents, gasoline, thinner, etc. Volatile organic compounds) such as monomers), heavy metal compounds, inorganic compounds, oils and the like.

  In addition, the underground soil purification system 10 which concerns on this embodiment is applicable not only to said ground 12, but various grounds, such as the ground 12 in which the poorly permeable layer 12A does not exist, for example.

  The underground soil purification system 10 includes a water shielding wall 14, an injection tank 16, an injection well 20, a pumping well 22, and a water treatment device 26. The underground soil purification system 10 employs a biomethod (biostimulation).

  In the biomethod, for example, an injection solution to which an active agent (nutrient) such as a hydrogen sustained-release agent or a yeast extract is added is injected from the injection well 20 into the contaminated soil 12B1 to decompose the contaminants in the contaminated soil 12B1. In this method, microorganisms (hereinafter referred to as “decomposing microorganisms”) are grown and activated to promote the purification of contaminants by the decomposing microorganisms.

  Further, in the underground soil purification system 10, the groundwater that has passed through the contaminated soil 12 </ b> B <b> 1 is pumped from the pumping well 22 and is subjected to water treatment by the water treatment device 26. In addition, after the above-mentioned activator is added in the injection tank 16, the groundwater subjected to the water treatment is injected again from the injection well 20 into the contaminated soil 12B1.

  Thus, in the underground soil purification system 10 according to the present embodiment, the contaminated soil 12B1 is purified while circulating the groundwater between the contaminated soil 12B1 and the water treatment device 26. Hereinafter, the configuration of each component of the underground soil purification system 10 will be described.

(Impermeable wall)
The impermeable wall 14 is formed in the aquifer 12B by concrete or ground improvement. The impermeable wall 14 is formed in a frame shape in plan view so as to surround the contaminated soil 12B1. This impermeable wall 14 penetrates the aquifer 12B, and its lower end is embedded in the hardly permeable layer 12A. This prevents the diffusion of groundwater contaminated with the contaminated soil 12B1. The impermeable wall 14 may be provided as necessary, and can be omitted as appropriate.

(Infusion tank)
The injection tank 16 stores an injection solution to be injected into the contaminated soil 12B1. A water treatment device 26 to be described later is connected to the injection tank 16 through a pipe 50, and groundwater treated by the water treatment device 26 is supplied. This groundwater is stored in the injection tank 16 as an injection solution. In addition, in the injection tank 16, the above-described activator or the like is appropriately added to the injection solution. That is, the injection tank 16 is an injection liquid adjustment tank that adjusts the injection liquid.

  An injection well 20 is connected to the injection tank 16 via a pipe 18. This pipe 18 is provided with an infusion pump (not shown). By operating this injection pump, the groundwater stored in the injection tank 16 is supplied to the injection well 20 via the pipe 18.

(Injection well and pumping well)
The injection well 20 is disposed on one end side of the partition region defined by the impermeable wall 14, and the pumping well 22 is disposed on the other end side of the partition region defined by the impermeable wall 14. Each injection well 20 and pumping well 22 are formed by excavating the ground 12. In addition, each injection well 20 and pumping well 22 penetrates the aquifer 12B of the ground 12 and reaches the hardly permeable layer 12A. The injection solution supplied from the injection tank 16 to the injection well 20 passes through the contaminated soil 12B1 and is pumped from the pumping well 22 as indicated by the arrow V.

  In addition, the number, arrangement | positioning, and length of the injection well 20 and the pumping well 22 can be suitably changed according to the range of the contaminated soil 12B1 used as purification object. Therefore, for example, the injection well 20 and the pumping well 22 do not necessarily need to be extended until they reach the hardly permeable layer 12A.

(Water treatment equipment)
The water treatment device 26 includes, for example, a filtration device that filters groundwater pumped from the pumping well 22. A pumping well 22 is connected to the water treatment device 26 via a pipe 24. The pipe 24 is provided with a pumping pump (not shown). By operating the pumping pump, the groundwater pumped from the pumping well 22 is supplied to the water treatment device 26.

  The groundwater supplied to the water treatment device 26 is water-treated by the water treatment device 26 to remove contaminants and the like. Then, the groundwater (treated water) treated by the water treatment device 26 is supplied to the injection tank 16 through the pipe 50.

  Next, an example of the injection method of the injection liquid according to the present embodiment will be described, and the effect of the granular filter backwashing method according to the present embodiment will be described.

  In the present embodiment, as described above, the activator is added to the injection solution to be injected into the ground 12. When the activator is added to the injection solution in this way, as shown in FIG. 2, microorganisms (microorganisms other than decomposing microorganisms) present in the injection solution 30 or contaminated soil consume (decompose) the active agent in the injection solution 30. ), The biofilm that causes clogging is likely to be generated at the injection port (not shown) of the injection well 20 and the surrounding ground 12B2 in the vicinity thereof. As a result, the injection efficiency of the injection solution 30 injected from the injection well 20 into the aquifer 12B may be reduced.

  As a countermeasure, in the present embodiment, the addition of the activator to the infusion solution 30 is temporarily stopped. More specifically, FIG. 3 shows the relationship between the addition period X of the activator with respect to the injection solution 30 (graph 66) and the liquid level 30U of the injection solution 30 in the injection well 20 (graph 60). Yes.

  A graph 60 shown in FIG. 3 shows a distance (depth) L (see FIG. 2) from the ground surface 12U of the ground 12 (see FIG. 2) to the liquid level 30U of the injected liquid 30 in the injection well 20. ing. A graph 62 shows the natural liquid level (natural water level) of the injection liquid 30 in the injection well 20. Further, the graph 64 shows the supply amount of the injection solution 30 supplied from the injection tank 16 to the injection well 20. This supply amount is substantially constant. Furthermore, the graph 66 shows the amount of activator added to the infusion solution 30. The amount added is substantially constant.

  As shown in FIG. 3, in this embodiment, the active agent is intermittently added to the infusion solution 30. Thereby, in the aquifer 12 </ b> B of the ground 12, the injection solution 30 to which the activator is not added is temporarily injected. As a result, the occurrence of a biofilm causing clogging at the injection port (screen portion or the like) of the injection well 20 and the surrounding ground 12B2 is suppressed.

  Further, when the activator disappears from the injection solution 30, the biofilm present in the injection port of the injection well 20 and the surrounding ground 12B2 is decomposed by itself or by microorganisms (microorganisms other than the decomposing microorganisms). The biofilm that has been decomposed and reduced in size is washed away by the injection solution 30 to which no active agent is added. Thereby, the clogging of the inlet of the injection well 20 and the surrounding ground 12B2 is eliminated. Therefore, in this embodiment, the injection solution 30 can be continuously injected from the injection well 20 into the aquifer 12 </ b> B of the ground 12.

  Here, as can be seen from the graph 60 in FIG. 3, the liquid level 30 </ b> U of the injection solution 30 in the injection well 20 gradually decreases during the addition restriction period Y in which the activator is not added to the injection solution 30. This is probably because the clogging of the injection port of the injection well 20 and the surrounding ground 12B2 is eliminated, and the injection efficiency of the injection solution 30 injected from the injection well 20 into the aquifer 12B is restored.

  As can be seen from FIG. 3, in the addition period X in which the activator is added to the injection solution 30, the liquid level of the injection solution 30 gradually increases in the injection well 20. This is because clogging occurs at the injection port (not shown) of the injection well 20 with the addition of the activator to the injection solution 30 and the injection of the injection solution 30 injected from the injection well 20 into the aquifer 12B. It is thought that efficiency was lowered

  By the way, as a method of eliminating the clogging of the injection port of the injection well 20, for example, a method of pumping the injection solution 30 in the injection well 20 with a pump or the like and back-cleaning it can be considered. However, in this reverse cleaning, since groundwater (contaminated water) contaminated by the contaminated soil 12B1 is also pumped, a treatment apparatus for the pumped groundwater is required. Further, the pump itself for pumping the injected liquid 30 in the injection well 20 is likely to be clogged, and the pump needs to be cleaned. Further, a clogging substance having high adhesiveness is difficult to be taken into the injection well 20, and clogging may not be eliminated.

  Further, as another method for eliminating the clogging of the injection port of the injection well 20, for example, a cleaning method by swabbing or jetting can be considered. However, these cleaning methods can be effective only in the vicinity of the injection port (screen portion) of the injection well 20, and the cleaning apparatus becomes a large scale.

  Further, as another method for eliminating the clogging of the injection port of the injection well 20, a method of injecting the injection liquid under pressure while the injection well 20 is sealed is conceivable. However, since the clogging of the injection port of the injection well 20 proceeds with the injection of the injection solution, it becomes difficult to eliminate the clogging. Furthermore, the ground 12 is destroyed with the pressure injection of the injection solution, and the injection solution 30 may escape from the ground surface.

  On the other hand, in the injection method of the injection liquid according to the present embodiment, the clogging of the injection port of the injection well 20 is efficiently performed with a simple configuration by temporarily stopping the addition of the activator to the injection liquid 30. Can be suppressed or eliminated.

  Next, a modified example of the method for adding the activator to the injection solution 30 will be described.

  For example, in the modification shown in FIG. 4, the addition of the activator to the infusion solution 30 is controlled according to time. Specifically, in the modification shown in FIG. 4, the activator is periodically added to the infusion solution 30. In this modification, a certain amount of activator Q is added to the infusion solution 30 during a certain addition period t1 after a certain addition restriction period t2. Thus, by controlling the timing of adding the activator to the infusate 30 with time, the addition control of the activator to the infusate 30 becomes easy. The addition period t1, the addition restriction period t2, and the addition amount Q of the activator can be changed as appropriate.

  For example, in the modification shown in FIG. 5, the addition of the activator to the injection solution 30 is controlled based on the liquid level 30U of the injection solution 30 in the injection well 20. Specifically, when clogging occurs in the injection port of the injection well 20 and the surrounding ground 12B2, the injection solution 30 injected from the injection well 20 into the ground 12 decreases, and the liquid of the injection solution 30 in the injection well 20 is reduced. The position (height of the injection liquid 30) 30U (see FIG. 2) rises. Based on the liquid level 30U of the injection solution 30, clogging of the injection port of the injection well 20 and the surrounding ground 12B2 is estimated.

  For example, when the liquid level 30U of the injection liquid 30 is lower than the lower limit L2, a predetermined amount of activator is added to the injection liquid 30, and when the liquid level 30U of the injection liquid 30 is higher than the upper limit L1. Then, the addition of the activator to the injection solution 30 is stopped. Thereby, clogging of the injection port of the injection well 20 and its surrounding ground 12B2 can be efficiently eliminated.

  In the modification shown in FIG. 6, the addition of the activator to the injection solution 30 is controlled based on the time and the liquid level 30U of the injection solution 30 in the injection well 20. Specifically, in the modification shown in FIG. 6, an upper limit value L1 and a lower limit value L2 are set for the liquid level 30U of the infusate 30 separately from the addition period t1 and the addition restriction period t2 of the activator.

  Then, when the liquid level 30U of the injection solution 30 becomes equal to or higher than the upper limit value L1, the addition of the activator to the injection solution 30 is stopped even during the addition period t1. On the other hand, when the liquid level 30U of the infusate 30 becomes equal to or lower than the upper limit L1, addition of the activator to the infusate 30 is started even during the addition restriction period t2.

  Further, in the modification shown in FIG. 7, in addition to the control based on the time shown in FIG. 6 and the liquid level 30U of the injection liquid 30 in the injection well 20, the liquid level 30U of the injection liquid 30 in the injection well 20 is the lower limit L1. When the following occurs, the injection well 20 is back-washed.

  In the reverse cleaning of the injection well 20, a pumping pump (not shown) is operated to pump up the injection liquid 30 in the injection well 20 and the ground water in the ground 12B2 around the injection well 20. Thereby, the biofilm adhering to the inlet of the injection well 20 and its surrounding ground 12B2 is removed. Therefore, clogging of the injection port of the injection well 20 is eliminated. In addition, the graph 60A shown in FIG. 7 shows the change in the liquid level 30U of the injection liquid 30 in the injection well 20 due to the reverse cleaning.

  In addition, microorganisms or enzymes that degrade the biofilm may be added to the injection solution 30 during the addition limit period t2 of the active agent. Thereby, clogging of the injection port of the injection well 20 and its surrounding ground 12B2 can be eliminated at an early stage.

  Moreover, in the said embodiment, although the addition of the activator with respect to the infusion solution 30 was stopped temporarily, the said embodiment is not restricted to this. For example, the amount of activator added to the infusate 30 may be temporarily reduced. That is, the active agent addition restriction period in the present embodiment is a concept including not only the case where the addition of the active agent to the infusion solution 30 is stopped, but also the case where the addition amount of the activator to the infusion solution 30 is decreased.

  Moreover, in the said embodiment, clogging of the injection hole etc. of the injection well 20 was eliminated by controlling addition of the activator with respect to the injection liquid 30, However, The said embodiment is not restricted to this.

  For example, an acidic additive such as sodium hydroxide may be periodically added to the injection solution 30 to make the injection solution 30 acidic, or the acidity of the injection solution 30 may be increased (for example, pH 8 or higher). . Thereby, it becomes easy to peel off the biofilm from the injection port of the injection well 20 or the like. Therefore, clogging of the injection port of the injection well 20 can be suppressed or eliminated.

  In addition, it is also possible to add a neutral additive to the infusion solution 30 instead of an acidic additive. In this case, clogging of the injection port of the injection well 20 and the like can be suppressed or eliminated while suppressing corrosion of the steel pipe constituting the injection well 20 and metal equipment such as a pump in the injection well 20.

  Further, for example, the injection solution 30 is heated to a temperature higher than the ground water in the ground 12 (aquifer 12b) (for example, 35 degrees or more). This suppresses the growth and propagation of microorganisms that cause biofilms. Therefore, clogging of the injection port of the injection well 20 can be suppressed or eliminated. Further, for example, the injection liquid 30 is heated to a temperature that is higher than the groundwater in the ground 12 (aquifer 12b) and at which the decomposed microorganisms are easily activated, so that the injection port of the injection well 20 is clogged. Can be suppressed or eliminated.

  Note that a heater such as a heater for heating the injection solution 30 may be provided in the injection tank 16 or in the injection well 20, for example.

  Further, for example, a bactericidal agent such as sodium hypochlorite may be periodically added to the injection solution 30. Thereby, the biofilm generated at the injection port of the injection well 20 or the like is easily destroyed (disinfected). Therefore, clogging of the injection port of the injection well 20 can be suppressed or eliminated.

  In the above embodiment, the step of temporarily stopping the addition of the active agent to the infusion solution 30 or the step of temporarily reducing the addition amount of the activator, the step of adding an acidic additive to the infusion solution 30, The step of heating the injection solution 30, the step of adding a bactericide to the injection solution 30, and at least one step of the various modifications described above can be included. Furthermore, the above embodiment and various modifications can be combined as appropriate.

  As mentioned above, although one embodiment of the present invention was described, the present invention is not limited to such an embodiment, and one embodiment and various modifications may be used in combination as appropriate, and the gist of the present invention will be described. Of course, various embodiments can be implemented without departing from the scope.

12 Ground 20 Injection well 30 Injection liquid 30U liquid level (liquid level of injection liquid)

Claims (3)

In an injection method of injecting an injection solution added with an activator that activates degrading microorganisms that decompose pollutants in the ground from the injection well to the ground,
Temporarily stopping the addition of the active agent to the infusion, or temporarily reducing the amount of the active agent added;
Adding an acidic additive to the infusion,
A step of heating the injection solution, and a step of adding a disinfectant to the injection solution,
Including at least one step of
Injection method of injection solution. Periodically performing at least one of the plurality of steps.
The injection method of the injection liquid according to claim 1. Performing at least one of the plurality of steps when the liquid level of the injection liquid in the injection well is a predetermined value or more;
The method for injecting an injection solution according to claim 1 or 2.

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