JP2006116509A - Method for estimating progress of purification at contaminated region beforehand, method for determining optimum place to arrange water pumping and water pouring wells, and method for estimating period required to purify contaminated region - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for estimating progress of purification at a contaminated region. <P>SOLUTION: The method for estimating progress of the purification at the contaminated region beforehand comprises the steps of collecting the soil in the contaminated region to carry out an indoor test of water-carrying purification, creating the first data showing change in concentration of a contaminated substance with time when the water-carrying purification is carried out at a predetermined flow amount, determining a detachable rate constant based on the first data in an adsorption expression of the contaminated substance containing the detachable rate constant of the contaminated substance to the soil, collecting the soil of the contaminated region to carry out the indoor test of purification by a microbe, creating the second data showing change in concentration of the contaminated substance with time when the microbe existing in the soil is cultivated to decompose the contaminated substance, and calculating a decomposition reaction rate constant based on the second data in a decomposition reaction expression of the contaminated substance containing the decomposition reaction rate constant of the contaminated substance by the microbe, and simulating change in concentration of contamination with time at the contaminated region three-dimensionally using the detachable rate constant and the decomposition reaction rate constant. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for predicting the purification process of a contaminated area in advance when a contaminated area contaminated with a pollutant in the field is purified by water and purified by microorganisms present in the contaminated area, and a period required for the purification of the contaminated area. And a method for determining the optimal location of the pumping well and water injection well.

  When contaminated with pollutants, we are purifying the contaminated area using water washing and technology (bioremediation technology) using pollutant-degrading microorganisms present in the contaminated area. When performing purification work, it is important to predict the progress in the process and predict the end time in understanding the construction period (planning for the purification work). The development of Japanese Patent Application Laid-Open No. 2004-151867 is underway.

  However, since the above-mentioned technology actually starts the purification work, it monitors the progress of the purification work of contaminated soil and groundwater, and predicts the end time of the purification work compared with the predicted value by simulation. Before the purification work, it is impossible to predict the progress of the purification process or the completion time of the purification work, such as the construction plan (for example, verification or planning of a facility plan that can be efficiently purified), budget, construction period, etc Quantitative evaluation and development of prediction methods are required to confirm the base of the product and the purification concept itself.

  Furthermore, because the geological structure and soil properties differ from site to site under on-site conditions, it was difficult to accurately predict the progress of water purification based on experience gained at different sites. .

  In addition, when water is washed through a contaminated area, it can be expected that the pollutant will be purified by microorganisms that decompose the pollutant, but the effects of water purification and microbial purification are not evaluated separately. Therefore, rational planning and construction management based on these effects were not performed.

Furthermore, since the abundance of microorganisms and the purification ability by microorganisms differ depending on the conditions at the site, it is difficult to accurately predict the progress of purification by microorganisms based on experience obtained at another site.
JP 2002-119951 A

  The present invention has been made in view of the above problems, and it is possible to predict the progress and end time of the process necessary for verifying or planning a purification facility plan such as the arrangement of wells, etc. It is an object of the present invention to provide a method for predicting the purification process in advance, a method for predicting the time required for purification of a contaminated area, and a method for determining an optimal location for the pumping well and water injection well.

  In the purification of contaminated areas by water flow cleaning, pollutants present in the soil gaps in the contaminated areas move together with the groundwater through the water flow and are collected, and the soil (solid phase) from the contaminated area is groundwater (liquid phase). It is expected that pollutants will elute and be collected together with groundwater.

  Therefore, when simulating the movement process of pollutants due to water purification, the advection diffusion method, which represents the process in which pollutants move in groundwater, and the process in which pollutants elute from the solid phase to the liquid phase are usually used. This is performed by using a linear or non-linear instantaneous balance expression. However, depending on the type of pollutant and the form of contamination, it may be difficult to simulate the movement process of pollutants by water purification using these mathematical formulas. For example, hydrophobic pollutants such as benzene are considered to desorb organic substances contained in contaminated soil, and the concentration of pollutants gradually decreases due to water purification over a long period of time.

  In water purification, purification of pollutants by microorganisms present in the contaminated area is also expected. Was not simulated.

  Therefore, the present inventors determined the desorption rate constant of the pollutant to the soil in the contaminated area from laboratory tests of water washing, and determined the decomposition reaction rate constant of the pollutant by microorganisms present in the contaminated area. Based on parameters calculated from laboratory tests and including these constants, it is possible to predict the purification process of the contaminated area in advance by three-dimensionally simulating changes in the contaminated area over time. Thought.

Therefore, the present inventors have created data showing the change over time in the concentration of pollutants when water purification is performed at a predetermined flow rate through a laboratory test of water purification, and the desorption rate in equation (1) By using the constant β as a variable and simulating the non-equilibrium adsorption equation expressed by the following equation (1) and the advection diffusion equation expressed by the following equation (2), water purification is performed at a predetermined flow rate. A function indicating the change with time of the concentration of the contaminant when it was performed was prepared, and the desorption rate constant β was determined by fitting these data. The parameters used in the simulation are the parameters obtained by laboratory experiments (see Table 1), and the longitudinal dispersion coefficient is the same as that of Gelhar et al. (A critical review of data on field-scale dispersion in aquifers, water Resour. Res., 28 (7), pp1955-1974, 1992), using 1/10 of the test scale.

  As a result, as shown in FIG. 1, the result of the laboratory test shows a slow gradient change, whereas the result of the simulation decreases linearly, but thereafter both decrease linearly in the same way. Became clear. In the selected nonequilibrium adsorption formula, the ease of elution from the solid phase to the liquid phase is expressed as a mathematical formula using the desorption rate constant. It was confirmed that there was a clear break point from the dominant period in which the concentration decrease was fast to the period in which the dissolution rate from the solid phase was dominant and the concentration decrease was slow.

  Based on the above, the desorption rate constant β of the pollutant is calculated by a laboratory test of water flow cleaning, and the non-equilibrium adsorption equation expressed by the following equation (1) and the advection diffusion expressed by the following equation (2) It is suggested that by simulating the equations together, it is possible to simulate changes in the concentration of pollutants in the soil in the contaminated area over time, and to predict the purification process of the contaminated area by water purification in advance. It was. From this, it is possible to simulate the time-dependent change in the concentration of contaminants in the soil in the contaminated area by calculating the decomposition reaction rate constant of the contaminants through laboratory tests for microbial purification and performing simulations. We thought that it was possible to predict in advance the purification process of the contaminated area. Thus, the present inventors have completed the present invention.

  In equation (1), ρs is the bulk density of the solid phase (soil), S is the concentration of contaminants in the solid phase, C is the concentration of contaminants in the liquid phase (groundwater), β is the desorption rate constant, Kd means an equilibrium distribution coefficient, and t means time.

  In Equation (2), C is the concentration of the contaminant in the liquid phase, D is the dispersion coefficient, V is the flow rate of water flowing through the contaminated area when passing through the contaminated area, θ is the porosity, and ρs is The solid density (soil) bulk density, S is the concentration of contaminants in the solid phase, t is the time, x is the distance in the x direction (the direction of the straight line connecting the injection well and the pumping well at the site). The letters (i and j etc.) mean vectors or tensor quantities, respectively.

  That is, the method according to the present invention is a method for predicting the purification process of the contaminated area when the contaminated area contaminated with the pollutant at the site is purified by water and purified by microorganisms present in the contaminated area. Collecting soil in the contaminated area and conducting a laboratory test for water purification, creating first data indicating the change over time in the concentration of the pollutant when water purification is performed at a predetermined flow rate, In the pollutant adsorption formula including the desorption rate constant of the pollutant to the soil, the desorption rate constant is determined based on the first data, and the soil in the contaminated area is collected and purified by the microorganism. Perform a laboratory test, create second data showing the change over time of the concentration of the pollutant when the pollutant is decomposed by culturing the microorganism present in the soil, In the decomposition reaction formula of the pollutant including the decomposition reaction rate constant of the pollutant, the decomposition reaction rate constant is calculated based on the second data, and the determined desorption rate constant and the calculated decomposition reaction rate constant are determined. Is used to three-dimensionally simulate the change over time of the contamination concentration in the contaminated area.

  Further, the method according to the present invention is a method for predicting the purification process of the contaminated area when the contaminated area contaminated with the pollutant at the site is purified by water and purified by microorganisms present in the contaminated area. Collecting soil in the contaminated area and conducting a laboratory test for water purification, creating first data indicating the change over time in the concentration of the pollutant when water purification is performed at a predetermined flow rate, The function of time and concentration obtained by combining the adsorption equation including the desorption rate constant of the contaminant to the soil and the advection diffusion equation determines the desorption rate constant that most closely approximates the first data. The soil in the contaminated area is collected and subjected to a laboratory test for purification by the microorganisms, and the change in the concentration of the contaminants with time when the microorganisms existing in the soil are cultured to decompose the contaminants is shown. In the second data, the absolute value of the slope of the graph representing the relationship between the logarithm of the concentration and the time with respect to the data in the range in which the concentration and the time are in a monotonically decreasing relationship is obtained by the microorganism. Calculating a time constant change of the contamination concentration in the contaminated region by using the determined desorption rate constant and the calculated decomposition rate constant as a decomposition reaction rate constant of the pollutant.

  The method according to the present invention is a method for predicting the time required for purification of a contaminated area when the contaminated area contaminated with a pollutant in the field is purified by water and purified by microorganisms present in the contaminated area. Collecting soil in the contaminated area and conducting a laboratory test for water purification, creating first data indicating the change over time in the concentration of the pollutant when water purification is performed at a predetermined flow rate, In the pollutant adsorption formula including the desorption rate constant of the pollutant to the soil, the desorption rate constant is determined based on the first data, and the soil in the contaminated area is collected and purified by the microorganism. Perform a laboratory test, create second data indicating the change over time of the concentration of the pollutant when the pollutant is decomposed by culturing microorganisms present in the soil, In the decomposition reaction formula of the pollutant including the decomposition reaction rate constant of the dyeing substance, the decomposition reaction rate constant is calculated based on the second data, and the determined desorption rate constant and the calculated decomposition reaction rate constant are calculated. And a three-dimensional simulation of a change in contamination concentration over time in the contaminated region, and calculating a period during which the concentration of the contaminant in the contaminated region reaches a predetermined concentration.

  Further, the method according to the present invention is a method for predicting a period required for purification of a contaminated area when a contaminated area contaminated with a pollutant at a site is purified by water and purified by microorganisms present in the contaminated area. The soil of the contaminated area is collected, the indoor water purification test is performed, and the first data showing the change over time in the concentration of the pollutant when the water purification is performed at a predetermined flow rate is created. The desorption rate constant is such that the function of time and concentration obtained by combining the adsorption equation including the desorption rate constant of the pollutant with respect to the soil and the advection diffusion equation most closely approximates the first data. Change in the concentration of the pollutant when the microorganism is present in the soil and decomposed by culturing the microorganism present in the soil. The second data is created, and in the second data, the absolute value of the slope of the graph representing the relationship between the logarithm of the density and the time with respect to the data in the range where the density and the time are monotonously decreasing Calculated as a decomposition reaction rate constant of the pollutant by microorganisms, using the determined desorption rate constant and the calculated decomposition reaction rate constant, three-dimensional simulation of the change in the concentration of contamination in the contaminated area over time, Calculating a period during which the concentration of the contaminant in the contaminated area reaches a predetermined concentration.

  The method according to the present invention includes a pumping well and a pouring well that reach a predetermined concentration in the shortest period when a contaminated area contaminated with a pollutant at a site is purified by water and purified by microorganisms present in the contaminated area. A method for determining an arrangement location with a water well, the data specifying a location where the pumping well and the injection well are arranged for a combination of a plurality of pumping wells and injection wells, a hydrogeological model in the contaminated area Using the data, the desorption rate constant of the pollutant with respect to the soil in the contaminated area, and the decomposition reaction rate constant of the pollutant by the microorganism, a three-dimensional simulation of the change over time in the contamination concentration in the contaminated area And before the contaminants in the contaminated area can be purified in the shortest period of time in the combination of the plurality of pumping wells and water injection wells. Determining the placement location of the water injection well and the pumping well, and the desorption rate constant of the pollutant is obtained by conducting the indoor purification test by sampling the soil in the contaminated area and at a predetermined flow rate. In the adsorption formula of the pollutant including the desorption rate constant of the pollutant with respect to the soil, the first data showing the change over time of the concentration of the pollutant when water purification is performed is performed. It is obtained by determining the desorption rate constant based on the data, and the decomposition reaction rate constant of the pollutant is present in the soil by collecting the soil in the contaminated area and conducting a laboratory test for purification by the microorganism. The second data showing the change over time of the concentration of the pollutant when the pollutant is decomposed by culturing the microorganism, and the pollutant containing the degradation rate constant of the pollutant by the microorganism is included. In the solution reaction formula, characterized in that it is obtained by calculating the decomposition reaction rate constant based on said second data.

  Further, the method according to the present invention provides a pumping well that reaches a predetermined concentration in the shortest period when water is purified through a contaminated area contaminated with a pollutant in the field and purified by microorganisms present in the contaminated area. For determining the location where the water well and the water injection well are arranged, and for a combination of a plurality of water wells and water injection wells, data for specifying the location where the water well and the water injection well are arranged, hydraulic in the contaminated area Using the geological model data, the desorption rate constant of the pollutant with respect to the soil in the contaminated area, and the decomposition reaction rate constant of the pollutant by the microorganism, the change over time of the contamination concentration in the contaminated area is three-dimensionally simulated. And in the combination of the plurality of pumping wells and injection wells, the pollutant in the contaminated area can be purified in the shortest time. Determining a place where the water injection well and the pumping well are arranged, and the desorption rate constant of the pollutant is obtained by sampling the soil in the contaminated area and conducting a laboratory test for water purification. The first data showing the change over time in the concentration of the pollutant when water purification is performed at a flow rate is created, and the adsorption formula including the desorption rate constant of the pollutant to the soil and the advection diffusion formula are combined. A function of time and concentration is obtained by determining the desorption rate constant that most closely approximates the first data, and the degradation rate constant of the contaminant is determined by the soil in the contaminated area. Collecting and conducting a laboratory test of purification by the microorganisms, creating second data indicating the change over time of the concentration of the contaminants when the microorganisms present in the soil are cultured and the contaminants are decomposed, To the second data And calculating the absolute value of the slope of the graph representing the relationship between the logarithm of concentration and time for data in a range where the concentration and time are monotonically decreasing as the decomposition reaction rate constant of the pollutant by the microorganism. It is obtained by these.

  The contaminant is, for example, a hydrophobic substance such as benzene.

  According to the present invention, a method for predicting the purification process of a contaminated area in advance, which can predict the progress and end time of processes necessary for verifying or planning a purification facility such as the arrangement of wells, It is possible to provide a method for predicting a period required for purification of a contaminated area, and a method for determining an optimal arrangement location of a pumping well and a water injection well. Accordingly, it is possible to verify and formulate a purification facility plan before starting the purification work, and to perform effective facility arrangement and the like.

  Further, according to the present invention, not only the purification effect by water washing but also the purification effect by microorganisms can be examined, so that a more effective purification plan can be performed.

  An embodiment for carrying out the present invention completed based on the above knowledge will be described in detail with reference to examples.

  The method of predicting the purification process of a contaminated area according to the present invention in advance is, for example, when it is confirmed that the soil is contaminated with a pollutant at a site such as a planned redevelopment site or a sold land. To be implemented. By this prediction method, it becomes possible to predict in advance the change in the concentration of the pollutant when the contaminated area contaminated with the pollutant is purified by water washing, and the purification process of the contaminated soil can be predicted in advance. It becomes possible. Further, since the purification process of the contaminated soil can be predicted in advance, it is possible to predict the period required for the purification of the contaminated area.

  Hereinafter, a method for predicting the purification process of a contaminated area according to an embodiment of the present invention in advance will be described with reference to the work flow diagram of the contaminated area purification plan in FIG.

  In the method of predicting the purification process of the contaminated area in advance, it is necessary to simulate the change over time of the contamination concentration in the contaminated area in three dimensions. In this simulation, the hydrogeological model of the contaminated area, the initial water level Distribution, initial concentration distribution, and migration / conversion of pollutants in the contaminated area when the contaminated area contaminated by the pollutant at the site is purified by water and purified by microorganisms present in the contaminated area (= contamination purification) As well as parameters associated with these equations.

  For the data related to the hydrogeological model, initial water level distribution, and initial concentration distribution of the contaminated area, various investigations (S201) are performed, boundary conditions of the contaminated area are set (S202), and initial conditions are set ( S203). For example, as shown in FIGS. 2 and 3, the data of the hydrogeological model (S308) of the contaminated area is analyzed by the conventional geological information survey (S301) and the observation of the boring core (S302). In addition, the water permeability coefficient (S305) for each soil layer in the contaminated area is analyzed by the on-site water permeability test (S304), and these analyzed data and the irrigation well used for water purification empirically or presumedly And wells such as pumping wells (S306) can be obtained by simulation based on data. If an error occurs in this simulation, the data may be discretized, or the condition setting at the end of the three-dimensional model of the contaminated region may be changed in this simulation (S307). Note that the data of the hydrogeological model (S308) of the contaminated area can be obtained by simulation using the above-mentioned various data and existing programs (for example, GMS (Groundwater Modeling System; BOSS international, etc.)). In the present embodiment, the hydrogeological model data of the contaminated area is created in S202, but may be created in S205.

  In addition, the initial water level distribution (S312) data of the contaminated area is obtained by, for example, measuring the water level distribution (S310) at each point of the contaminated area by measuring the pore water level of the soil at each point of the contaminated area or measuring the pore water pressure of the soil (S309). ) And by interpolating the data of the water level distribution in the contaminated area from the obtained data.

  On the other hand, the initial concentration distribution (S315) data of the contaminated area is obtained by analyzing the concentration distribution (S314) at each point of the contaminated area, for example, by measuring the concentration of the pollutant at each point of the contaminated area (S313). It can be obtained by interpolating density distribution data in the contaminated area from the obtained data. In addition, the concentration measurement of the pollutant (S313) may be performed in accordance with, for example, a measurement method defined in Japanese Industrial Standards, or may be performed in a method in accordance with the Notification of the Environment Agency.

  Selection of mathematical expressions expressing the migration / conversion of pollutants in the contaminated area and acquisition of parameters associated with the mathematical expressions (S204) can be performed as follows. In addition, the “mathematical expression expressing substance transfer / conversion” means a mathematical expression expressing a purification process using water washing, a purification process using microorganisms, and the like. Hereinafter, selection of mathematical expressions expressing the purification process by water flow cleaning and the purification process by microorganisms will be described with examples.

<Selection of mathematical formula and parameter acquisition to express purification process by water flow cleaning>
The selection of a mathematical expression that expresses the purification process by water flow cleaning is performed by first collecting soil in the contaminated area, conducting a laboratory test of water flow purification, and determining the concentration of the pollutant when water flow purification is performed at a predetermined flow rate. This is done by creating data showing changes over time and selecting a mathematical formula that can best reproduce (approximate) this data. In this way, by selecting a mathematical formula that can best reproduce the results of laboratory tests, it is possible to accurately predict changes in the concentration of pollutants due to water purification that reflects the characteristics of contaminated soil in the field. become.

  In addition, as said numerical formula, the advection diffusion equation and the simultaneous equation of an adsorption type can be used, for example. The adsorption equation may be any contaminant adsorption equation including a desorption rate constant of the contaminant to the soil. For example, a non-equilibrium adsorption equation (for example, the above equation (1)), 2 A heavy gap adsorption type (for example, the following formula (3)) can be used. When the above equation (1) is used as the adsorption equation, for example, the above equation (2) can be used as the advection diffusion equation. When the above equation (3) is used as the adsorption equation, for example, the following equation (4) can be used as the advection diffusion equation. In addition, the indoor test for water flow purification uses, for example, a column apparatus as shown in FIG. 4 and the soil volume collected from the contaminated area is applied to a soil column having a water flow port and a water discharge port. Packed to a density, let the water flow through the soil column at a predetermined flow rate, pass water through the soil column, and collect a predetermined amount of water that has passed through the soil column at a predetermined interval from the soil column drain And measuring the concentration of contaminants.

In equation (3), θim is the porosity occupied by the phase in which groundwater cannot move, Cm is the concentration of contaminants in the phase in which groundwater can move, and Cim is the contaminant in phases in which groundwater cannot move. , Sim is the concentration of contaminants in the solid phase in contact with the phase in which groundwater cannot move, ρs is the bulk density of the solid phase (soil), and f is in contact with the phase in which groundwater can move on the solid surface. The ratio means β, the desorption rate constant, and t means time.

In equation (4), θm is the porosity occupied by the phase in which groundwater can move, θim is the porosity occupied by the phase in which groundwater cannot move, and Cm is the contaminant in the phase in which groundwater can move. Cim is the concentration of contaminants in the phase in which groundwater cannot move, Sm is the concentration of contaminants in the solid phase that contacts the phase in which groundwater can move, and Sim is in contact with the phase in which groundwater cannot move The concentration of contaminants in the solid phase, Vm is the flow velocity through which the groundwater can move, ρs is the bulk density of the solid phase (soil), and f is the ratio of contact with the phase where groundwater can move on the solid surface. , Dm is the apparent dispersion coefficient of the phase in which the groundwater can move, β is the desorption rate constant, t is the time, x is the distance in the x direction (the direction of the straight line connecting the injection well and the pumping well at the site) , Subscripts (i and j etc.) are vector Each means the amount of the tensor.

The parameter is determined by the selected mathematical formula. For example, when the above formulas (1) and (2) are selected, the bulk density ρs of the solid phase in the contaminated area, the partition coefficient Kd between the solid phase and the liquid phase in the contaminated area for the contaminant, Dispersion coefficient D (x, y, z = D _L , D _T , D _T ) of pollutants when water is passed, pollutants dissolved in the water in the polluted area move with water when passed through the polluted area Parameters such as the flow velocity (ie, groundwater flow velocity; Darcy flow velocity) V (x, y, z = Vx, Vy, Vz), the porosity θ of the contaminated area, and the desorption rate constant β are determined.

  Here, the bulk density ρs of the solid phase, the distribution coefficient Kd, and the porosity θ can be obtained by analyzing the contaminated soil in the contaminated area by a conventional method. In addition, as the bulk density ρs of the solid phase, a wet density in a compacted state of contaminated soil is usually used. The bulk density ρs of the solid phase can be obtained, for example, by collecting an undisturbed sample from the contaminated region by soil boring, measuring its volume V and mass M, and dividing the mass M by the volume V. In addition, the distribution coefficient Kd is, for example, the content So [mg / kg] of the initial pollutant in the contaminated soil of the soil column obtained by the laboratory test of water purification described above in the permeate of the initial soil column. However, the present invention is not limited to such a method, and the distribution coefficient Kd may be obtained by a normal batch equilibrium test. As for the porosity θ, for example, the water content ratio ω of the sample for which the bulk density ρs of the solid phase is measured and the density d of the soil particles are in accordance with the method of the Japan Society for Geotechnical Engineering (JSF T 111-1990 and JSF T 121-1990). And can be obtained using the formula: θ = 1− [ρs / d (1 + ω)].

  The dispersion coefficient D of the pollutant can also be obtained by analyzing the contaminated soil in the contaminated area by a conventional method. However, a literature (eg, a critical review of data on field-scale by Gelhar et al. dispersion in aquifers, Water Resour. Res., 28 (7), pp1955-1974, 1992)). In addition, the flow rate of groundwater can be measured and analyzed by conventional methods. Specifically, a method using osmotic flow analysis can be mentioned. Furthermore, the desorption rate constant β can be determined based on the graph showing the change over time in the concentration of the pollutant obtained from the indoor test for water purification as described above. For example, the function of time and concentration obtained by combining the adsorption equation including the desorption rate constant of pollutants to the soil and the advection diffusion equation shows the change over time in the concentration of pollutants obtained from laboratory tests for water purification. The desorption rate constant β can be obtained by determining the desorption rate constant that most closely approximates the graph shown.

  In the present embodiment, a mathematical expression expressing the purification process by water flow cleaning is selected. However, a predetermined mathematical expression may be used.

<Selection of mathematical expression expressing purification process by microorganisms>
The selection of a mathematical formula that expresses the purification process by microorganisms is performed by first collecting soil in the contaminated area, conducting laboratory tests for purification by microorganisms, cultivating microorganisms present in the soil, and degrading the contaminants. This is done by creating data indicating the change in concentration over time and selecting a mathematical expression that can best reproduce (approximate) this data. In this way, by selecting mathematical formulas that can best reproduce the results of laboratory tests, it is possible to accurately predict changes in the concentration of pollutants due to microbial purification that reflects the characteristics of contaminated soil in the field. Become.

  The mathematical expression may be any pollutant decomposition reaction formula including the degradation rate constant of the pollutants by microorganisms. For example, a primary reaction formula (for example, the following formula (5)) A monod formula (for example, the following formula (6)) can be used. Moreover, the laboratory test of purification by microorganisms may be, for example, a batch type or a continuous type. In the case of a batch type, for example, a predetermined amount of contaminated soil collected from a contaminated area, a predetermined amount of water, and a predetermined amount of contaminant are put in a container (for example, a brown pressure-resistant bottle) and exist in the soil. If the microorganisms are aerobic, replace the gas phase part in the container with oxygen and seal the container, while if the microorganisms present in the soil are anaerobic, remove the gas phase part in the container. Substituting with nitrogen or carbon dioxide, sealing the container, culturing microorganisms present in the container, collecting the solution in the container at predetermined intervals, and measuring the concentration of contaminants in the solution Also good.

In equation (5), [HC] represents the concentration of the contaminant in the liquid phase, κ represents the decomposition reaction rate constant of the contaminant by the microorganism, and t represents time.

In equation (6), [HC] is the concentration of the pollutant in the liquid phase, [O ₂ ] is the concentration of oxygen dissolved in the liquid phase, κ is the decomposition reaction rate constant of the pollutant by the microorganism, K Is the half constant, Y is the ratio of the mass of oxygen required to consume 1 mol of pollutant and the mass of 1 mol of pollutant, and t is the time.

  The parameter is determined by the selected mathematical formula. For example, when the above formula (5) is selected, the decomposition reaction rate constant κ of the contaminant by the microorganism is determined. As described above, the degradation reaction rate constant κ of the pollutant by the microorganism can be calculated based on the graph showing the change over time in the concentration of the pollutant obtained from the laboratory test for purification by the microorganism. For example, if the degradation reaction formula for the pollutant containing the degradation reaction rate constant κ is a first-order reaction formula, the concentration and time in the graph showing the change over time in the concentration of the pollutant obtained from the laboratory test of purification by microorganisms The decomposition reaction rate constant κ can be obtained by calculating the absolute value of the slope of the graph representing the relationship between the logarithm of the concentration and time for the data in a range in which the monotonic decrease relationship is as the decomposition reaction rate constant. .

  In the present embodiment, a mathematical expression expressing a purification process by microorganisms is selected, but a predetermined mathematical expression may be used.

<3D simulation of contamination concentration over time in the contaminated area>
The hydrogeological model data, the initial water level distribution data, the initial concentration distribution data of the contaminated area, the mathematical expressions expressing the migration / conversion of pollutants, and the parameters associated with those mathematical expressions obtained as described above. By performing the simulation based on this, it is possible to three-dimensionally simulate the temporal change of the contamination concentration in the contamination region. As a mathematical expression expressing the migration / conversion of the pollutant, for example, the above formula (1), formula (2), and formula (5) are selected to determine the desorption rate constant β and the decomposition reaction rate constant κ. When calculation is performed, the following formula (7) can be used, and the above-described formula (1), formula (2), and formula (6) are selected to determine the desorption rate constant β and the decomposition reaction rate. When the constant κ is calculated, the following equation (8) can be used.

In equation (7), [HC] is the concentration of the contaminant in the liquid phase, [HC] _S is the concentration of the contaminant in the solid phase, D is the dispersion coefficient, and V is the contamination when water is passed through the contaminated area. The flow rate of contaminants dissolved in water in the region with water, θ is the porosity, ρs is the solid density (soil) bulk density, κ is the decomposition reaction rate constant, t is the time, x is the time The distance in the x direction (the direction of the straight line connecting the water injection well and the pumping well at the site), and the subscripts (i and j etc.) mean the vector or tensor amount.

In formula (8), [HC] is the concentration of contaminants in the liquid phase, [HC] _S is the concentration of contaminants in the solid phase, [O ₂ ] is the concentration of oxygen dissolved in the liquid phase, [ O ₂ ] _S is the oxygen concentration in the solid phase, D is the dispersion coefficient, v is the flow rate of the contaminant dissolved in the water in the contaminated area when water is passed through the contaminated area, and θ is the porosity. Ρs is the bulk density of the solid phase (soil), κ is the decomposition rate constant, K is the half constant, Y is the oxygen mass and 1 mol of pollutant required to consume 1 mol of pollutant T is the time, x is the distance in the x direction (the direction of the straight line connecting the injection well and the pumping well at the site), and the subscripts (i and j, etc.) are the vector or tensor quantity. means.

  As described above, it is possible to clearly grasp the purification effect by washing with water and the purification effect by microorganisms by three-dimensionally simulating the temporal change of the contamination concentration in the contaminated area. The purification process can be accurately predicted. Therefore, it is possible to calculate a period during which the concentration of the contaminant in the contaminated area reaches a predetermined concentration (for example, a reference value determined by the Environment Agency). It is also possible to verify and formulate a purification facility plan that can efficiently purify the contaminated area. In addition, as purification equipment, it is the arrangement | positioning location of the injection well and pumping well required for water flow washing | cleaning, the arrangement number of those wells, etc., for example.

  The location of the injection wells and pumping wells required for water washing is determined by arranging the injection wells and the pumping wells at the predetermined locations, and measuring the contamination concentration in the contaminated area over time according to the location of each well. A three-dimensional simulation is performed, and it is determined whether or not the purification effect by water washing and microorganisms is sufficient, that is, whether or not the purification effect can be purified in the scheduled purification period (S206; see FIG. 2). If it is determined (S206; No), the process proceeds to S306, where the location of each well is changed or the number of wells is increased, and the concentration of contamination in the contaminated area due to those locations changes over time. The change is simulated three-dimensionally (S205). On the other hand, when it is determined in S206 that purification is possible (S206; Yes), purification of the contaminated area is started (S207).

  In this way, by verifying and planning the purification equipment plan, it becomes possible not only to quantify the purification work plan, budget, construction period, etc., but also to prevent unnecessary capital investment, The purification work can be performed smoothly. In this embodiment, it is determined whether the purification effect can be purified in the scheduled purification period, and if it is determined that purification is impossible, the location of each well is changed or the number of each well is arranged. The pumping well that reaches a predetermined concentration in the shortest period can be obtained by three-dimensionally simulating the time-dependent change of the contamination concentration in the contaminated area depending on the arrangement location (S206 → S306 → S205). It is possible to determine the location of the injection well, but for a combination of multiple pumping wells and injection wells, data for identifying the location where the pumping well and injection well are placed, hydrogeological model data in the contaminated area, Using the rate of desorption of pollutants to the soil in the contaminated area and the rate constant for the decomposition of pollutants by microorganisms, the change over time in the contaminated area is three-dimensional. By simulating and determining the location of the injection well and the pump well where the pollutants in the contaminated area can be purified in the shortest period among the combinations of multiple pump wells and injection wells. It is good also as determining the arrangement | positioning place of a pumping well and a water injection well which reaches a predetermined density | concentration. With this determination method, it is possible to quickly determine the optimal placement location of the pumping well and the water injection well.

  In the present embodiment, a method for predicting the purification process of a contaminated area in the case of performing water washing and purification with microorganisms in advance, a method for predicting the time required for purification of the contaminated area, and an optimal pumping well and injection well However, instead of these purification methods, purification by aeration cleaning (for example, air sparging method) or soil gas suction method (for example, vacuum suction method) may be applied. In addition to these purifications, purification by aeration cleaning or a soil gas suction method may be applied. When applying purification by aeration cleaning or soil gas suction method, soil in the contaminated area is collected, subjected to laboratory tests, and data showing the changes in the concentration of pollutants over time when prescribed treatment is performed. It is considered that the change over time in the contamination concentration in the contaminated region can be simulated three-dimensionally by creating and selecting a mathematical formula that reproduces this data, and acquiring parameters associated with this mathematical formula.

  In the present embodiment, each simulation is performed using a personal computer in which a program for performing each simulation is installed, but is not limited thereto.

== Other Embodiments ==
As described above, the construction management method in the case of starting construction according to the determined location of the pumping well and the water injection well will be described. FIG. 5 is a diagram illustrating a flowchart for performing construction management according to another embodiment.

  First, an assumed concentration change is set by numerical analysis (S501), and purification facilities are planned such as the location and number of injection wells and pumping wells. The setting of the assumed density change by numerical analysis is performed according to S201 to S207 in FIG.

  Based on the plan, water injection wells and pumping wells are arranged in the contaminated area at the site, aerated water or degassed water is passed through the water injection wells, and purification work is performed (S502). After a predetermined period of time, the groundwater and soil at each point are collected, the concentration of the pollutant is measured, and the groundwater and soil contamination concentration distribution in the contaminated area is analyzed (S503). With reference to the concentration distribution (measured value) obtained by this analysis, it is determined whether the concentration of the pollutant in the contaminated area satisfies the purification standard, that is, whether it reaches the standard value or less determined by the Environment Agency. Judgment is made (S504). As a result, when it is determined that the purification standard is satisfied (S504; Yes), the purification work is terminated. On the other hand, when it is determined that the purification standard is not satisfied (S504; No), the measured value is assumed by comparing with the concentration distribution (presumed concentration) of the contamination concentration in the contaminated region after the predetermined period predicted by the simulation. It is determined whether or not the concentration is equal to or lower than the concentration (S505). As a result, when it is determined that the measured value is equal to or lower than the assumed concentration (S505; Yes), the process proceeds to S502 and the construction is continued. On the other hand, when it is determined that the measured value is equal to or lower than the measured concentration (S505; No), the initial model is reviewed by numerical analysis (S506) and the purification equipment is reviewed (S507). Numerical analysis will be performed again. Thus, by performing construction management, it is possible to accurately grasp the progress of the purification work after the start of the purification work, and it is possible to take an appropriate measure according to the progress.

  As described above, the present invention has been described with reference to the embodiment. However, for those skilled in the art, the present invention is not limited to the embodiment described in the present application, and many modifications and implementation examples are described in the above embodiment of the present invention. It is clear that this can be done.

In one Embodiment of this invention, it is a figure which shows the time-dependent change of the density | concentration of the pollutant by the indoor test of water flow purification, and the time-dependent change of the density | concentration of the pollutant obtained by simulating. In one Embodiment of this invention, it is a figure which shows the work flow of the purification plan of a contamination area | region. In one Embodiment of this invention, it is a figure which shows the flow for obtaining hydrogeological model data, initial stage water level distribution data, and initial density distribution data. In one Embodiment of this invention, it is a figure which shows the structure of the column experiment apparatus used for the laboratory test of water flow purification. In other one Embodiment, it is a figure which shows the flowchart for performing construction management.

Claims (11)

A method for predicting the purification process of the contaminated area when purifying the contaminated area contaminated with a pollutant at the site and purifying with a microorganism present in the contaminated area,
Collecting soil in the contaminated area and conducting a laboratory test for water flow purification, creating first data indicating the change over time in the concentration of the pollutant when water purification is performed at a predetermined flow rate,
In the pollutant adsorption formula including a desorption rate constant of the pollutant to the soil, the desorption rate constant is determined based on the first data;
A second test is performed to collect the soil in the contaminated area and perform a laboratory test for purification by the microorganisms, and to show the change over time in the concentration of the contaminants when the microorganisms existing in the soil are cultured to decompose the contaminants. Create data,
In the decomposition reaction formula of the pollutant including the decomposition reaction rate constant of the pollutant by the microorganism, the decomposition reaction rate constant is calculated based on the second data,
Using the determined desorption rate constant and the calculated decomposition reaction rate constant, three-dimensionally simulating the change over time of the contamination concentration in the contaminated region,
A method comprising the steps of: A method for predicting the purification process of the contaminated area when purifying the contaminated area contaminated with a pollutant at the site and purifying with a microorganism present in the contaminated area,
Collecting soil in the contaminated area and conducting a laboratory test for water flow purification, creating first data indicating the change over time in the concentration of the pollutant when water purification is performed at a predetermined flow rate,
The function of time and concentration obtained by combining the adsorption equation including the desorption rate constant of the contaminant to the soil and the advection diffusion equation determines the desorption rate constant that most closely approximates the first data. And
A second test is performed to collect the soil in the contaminated area and perform a laboratory test for purification by the microorganisms, and to show the change over time in the concentration of the contaminants when the microorganisms existing in the soil are cultured to decompose the contaminants. Create data,
In the second data, the absolute value of the slope of the graph showing the relationship between the logarithm of the concentration and the time with respect to the data in the range where the concentration and the time are in a monotonously decreasing relationship is the decomposition reaction rate of the pollutant by the microorganism. Calculated as a constant,
Using the determined desorption rate constant and the calculated decomposition reaction rate constant, three-dimensionally simulating the change over time of the contamination concentration in the contaminated region,
A method comprising the steps of: Select the degradation reaction formula of the pollutant by the microorganism that most closely approximates the second data,
The method according to claim 1, wherein a decomposition reaction formula of the pollutant by the selected microorganism is used for the simulation. Select the pollutant adsorption formula that most closely approximates the first data,
The method according to claim 1, wherein the selected adsorption formula of the contaminant is used for the simulation.   The indoor test for water flow purification includes a step of filling contaminated soil collected from the contaminated area into a column having a water flow port and a water discharge port, and water is passed from the water flow port of the column at a predetermined flow rate to the column. Including a step of passing water, a step of collecting a predetermined amount of water that has passed through the column at a predetermined interval from a drain outlet of the column, and a step of measuring a concentration of the contaminant in the collected water. The method according to claim 1, characterized in that:   The laboratory test for purification by microorganisms includes a step of putting a predetermined amount of contaminated soil collected from the contaminated area, a predetermined amount of water, a predetermined amount of the contaminant into the container, and a gas phase portion in the container. Substituting oxygen, nitrogen, or carbon dioxide according to the growth conditions of the microorganism to seal the container, culturing the microorganism present in the container, and collecting the solution in the container at predetermined intervals The method according to claim 1, comprising a step and a step of measuring a concentration of the contaminant in the collected solution.   The parameters are the solid density of the solid phase in the contaminated area, the partition coefficient between the solid phase of the contaminated area and the liquid phase of the contaminated area with respect to the pollutant, and the dispersion of the pollutant when water passes through the contaminated area. Coefficient, flow rate when the pollutant dissolved in the water in the contaminated area moves together with the water when passing through the contaminated area, the effective porosity of the contaminated area, the water before purifying the contaminated area through the water The concentration distribution data of the pollutant in the contaminated area, the water level distribution data in the contaminated area before water purification of the contaminated area, and the hydrogeological model data in the contaminated area are included. 7. The method according to any one of 6. A method for predicting a period required for purification of a contaminated area when a contaminated area contaminated with a pollutant at a site is purified by water and purified by microorganisms present in the contaminated area,
Collecting soil in the contaminated area and conducting a laboratory test for water flow purification, creating first data indicating the change over time in the concentration of the pollutant when water purification is performed at a predetermined flow rate,
In the pollutant adsorption formula including a desorption rate constant of the pollutant to the soil, the desorption rate constant is determined based on the first data;
A second test is performed to collect the soil in the contaminated area and perform a laboratory test for purification by the microorganisms, and to show the change over time in the concentration of the contaminants when the microorganisms existing in the soil are cultured to decompose the contaminants. Create data,
In the decomposition reaction formula of the pollutant including the decomposition reaction rate constant of the pollutant by the microorganism, the decomposition reaction rate constant is calculated based on the second data,
Using the determined desorption rate constant and the calculated decomposition reaction rate constant, three-dimensional simulation of the change over time in the contamination concentration in the contaminated region,
Calculating a period during which the concentration of the contaminant in the contaminated area reaches a predetermined concentration;
A method comprising the steps of: A method for predicting a period required for purification of a contaminated area when a contaminated area contaminated with a pollutant at a site is purified by water and purified by microorganisms present in the contaminated area,
Collecting soil in the contaminated area and conducting a laboratory test for water flow purification, creating first data indicating the change over time in the concentration of the pollutant when water purification is performed at a predetermined flow rate,
The function of time and concentration obtained by combining the adsorption equation including the desorption rate constant of the contaminant to the soil and the advection diffusion equation determines the desorption rate constant that most closely approximates the first data. And
A second test is performed to collect the soil in the contaminated area and perform a laboratory test for purification by the microorganisms, and to show the change over time in the concentration of the contaminants when the microorganisms existing in the soil are cultured to decompose the contaminants. Create data,
In the second data, the absolute value of the slope of the graph showing the relationship between the logarithm of the concentration and the time with respect to the data in the range where the concentration and the time are in a monotonously decreasing relationship is the decomposition reaction rate of the pollutant by the microorganism. Calculated as a constant,
Using the determined desorption rate constant and the calculated decomposition reaction rate constant, three-dimensional simulation of the change over time in the contamination concentration in the contaminated region,
Calculating a period during which the concentration of the contaminant in the contaminated area reaches a predetermined concentration;
A method comprising the steps of: Decide where to place the pumping well and the water injection well so that they reach the specified concentration in the shortest period when the contaminated area contaminated with pollutants is purified on the site and purified by microorganisms present in the contaminated area. A way to
Data for specifying the location where the pumping well and the water injection well are arranged for a combination of a plurality of pumping wells and water injection wells, hydrogeological model data in the contaminated area, desorption of the pollutant from the soil in the contaminated area Using the rate constant and the degradation reaction rate constant of the pollutant by the microorganism, three-dimensionally simulating the temporal change of the contamination concentration in the contaminated area; and
In the combination of the plurality of pumping wells and water injection wells, determining the location of the water injection wells and the pumping wells that can purify the pollutants in the contaminated area in the shortest period;
Including
The desorption rate constant of the pollutant indicates the change over time in the concentration of the pollutant when the soil in the contaminated area is collected, subjected to the indoor test of the water purification, and the water purification is performed at a predetermined flow rate. In the pollutant adsorption equation including the desorption rate constant of the pollutant to the soil, the data is obtained by determining the desorption rate constant based on the first data,
The pollutant decomposition reaction rate constant is determined by collecting the soil in the contaminated area, conducting a laboratory test for purification by the microorganism, cultivating the microorganism present in the soil, and decomposing the pollutant. 2nd data showing the change over time of the concentration of the pollutant in the degradation reaction equation of the pollutant including the degradation rate constant of the pollutant by the microorganism, the degradation reaction rate constant based on the second data A method characterized by being obtained by calculating. Decide where to place the pumping well and the water injection well so that they reach the specified concentration in the shortest period when the contaminated area contaminated with pollutants is purified on the site and purified by microorganisms present in the contaminated area. A way to
Data for specifying the location where the pumping well and the water injection well are arranged for a combination of a plurality of pumping wells and water injection wells, hydrogeological model data in the contaminated area, desorption of the pollutant from the soil in the contaminated area Using the rate constant and the degradation reaction rate constant of the pollutant by the microorganism, three-dimensionally simulating the temporal change of the contamination concentration in the contaminated area; and
In the combination of the plurality of pumping wells and water injection wells, determining the location of the water injection wells and the pumping wells that can purify the pollutants in the contaminated area in the shortest period;
Including
The desorption rate constant of the pollutant indicates the change over time in the concentration of the pollutant when the soil in the contaminated area is collected, subjected to the indoor test of the water purification, and the water purification is performed at a predetermined flow rate. A function of time and concentration obtained by combining the adsorption equation including the desorption rate constant of the pollutant with respect to the soil and the advection diffusion equation so that the first data is most approximated. Obtained by determining the desorption rate constant,
The pollutant decomposition reaction rate constant is determined by collecting the soil in the contaminated area, conducting a laboratory test for purification by the microorganism, cultivating the microorganism present in the soil, and decomposing the pollutant. The second data showing the time-dependent change of the concentration of the graph is created. A method comprising obtaining an absolute value of a slope as a decomposition reaction rate constant of the pollutant by the microorganism.