Pretreatment method for X-ray fluorescence analysis or screening, method for measuring elements contained in agricultural organic materials, and screening method for agricultural organic materials.

Abstract

This process aims to create a state suitable for the component analysis of agricultural organic materials using activated precipitates from wastewater treatment. [Solution] When wastewater in the field to be analyzed is treated using the activated sludge method, the amount of interfering components that reduce the accuracy of X-ray fluorescence analysis of the target element is reduced from agricultural organic material derived from the wastewater treatment activated precipitate produced. The organic material with reduced interfering components is crushed into granules, the granules are classified to a particle size below a predetermined size, a specific amount of the target element is added to the granules below the predetermined particle size, and the granules with the specific amount of the target element added are stirred to make the target element uniformly distributed in the granules. A sample for a calibration curve is prepared, the target element is subjected to X-ray fluorescence analysis using the calibration curve sample to obtain a first measurement value, the target element is subjected to a reference analysis using the calibration curve sample, which has a different measurement principle than X-ray fluorescence analysis to obtain a second measurement value, and a calibration curve is determined from the correlation between the first and second measurement values.

Description

Technical Field

[0001] The present invention relates to a pretreatment method for fluorescence X-ray analysis or screening, a method for measuring elements contained in agricultural organic materials, and a method for screening agricultural organic materials. More specifically, the present invention relates to a pretreatment method for fluorescence X-ray analysis or screening for analyzing and measuring harmful components such as heavy metals and other contained elements in agricultural materials using wastewater treatment activated sludge as a raw material, a method for measuring elements contained in agricultural organic materials, and a method for screening agricultural organic materials. Here, the "wastewater treatment activated sludge" is defined in the raw material standard No. 26 of the second in the "Case of storing the official standards of ordinary fertilizers, etc. based on the Law on Ensuring the Quality of Fertilizers, etc." (amended on July 10, 2024, and implemented on August 9, 2024) in Japan.

Background Art

[0002] Agricultural organic materials using wastewater treatment activated sludge, which are used as fertilizers and soil conditioners in agriculture, have attracted attention as one of the solutions to the energy and environmental problems faced by agriculture centered on chemical fertilizers. However, since this agricultural organic material is derived from wastewater treatment activated sludge, it may contain harmful substances (especially those harmful to the human body) such as heavy metals, and regulations are set for the content of heavy metals and the like that can be shipped as products.

[0003] Therefore, in the case of agricultural organic materials using the above-mentioned wastewater treatment activated sludge, inspection of the above-mentioned harmful substances is essential during productization. Conventionally, the inspection of this harmful substance, for example, heavy metals, has been carried out by a measurement method based on the general rules of atomic absorption spectrometry defined in JIS K 0121 within the official method for heavy metal measurement, for example, the "Test Methods for Fertilizers, etc. (2024)" defined by the National Institute of Agrobiological Sciences (FAMIC).

[0004] However, this measurement method, due to its specifications, involves an extremely complex process, requiring a certain level of knowledge and skill from the person performing the measurement. Furthermore, the analysis period takes several days or more, resulting in high personnel and time costs. In addition, heavy metal wastewater is generated with each measurement, in addition to the financial cost of treating the heavy metal wastewater, which also places an environmental burden on the environment. In other words, the testing of the aforementioned hazardous substances itself has the contradiction of burdening the environment. Moreover, in Japan, organic materials derived from activated precipitates of wastewater treatment require analysis using official methods at least four times a year, for example, under the standard of "microbial phosphate fertilizer." Currently, not all lots of organic materials produced are subject to analysis, but from the perspective of safety of fertilizers and soil conditioners, there is a good chance that analysis of all lots will be socially required in the future.

[0005] To solve the above problems, a method is needed that is easy to operate, requires little analysis time, and produces no or less waste liquid containing heavy metals and other hazardous substances with each measurement. One such method is "X-ray fluorescence analysis." This X-ray fluorescence analysis method is a non-destructive analytical method used for the analysis and quantification of components in a wide range of fields. Because it is a non-destructive analytical method, it does not require the extraction of components using chemicals such as acids or alkalis. Therefore, it has the advantage of providing measurement results quickly compared to analytical methods that require chemical treatment. In recent years, handheld analytical instruments have also become available, making it possible for people without scientific knowledge or analytical skills to perform measurements.

[0006] As an example of component analysis using X-ray fluorescence analysis, Patent Document 1 (Japanese Patent Publication No. 2023-070985) proposes a method for quantifying chloride ions in concrete structures with the aim of early detection of the extent of salt damage in concrete. The method for determining chloride ions in concrete structures proposed in Patent Document 1 comprises: a sampling step of drilling holes in concrete structure A and collecting concrete particles; and a measurement step of measuring the chloride ion concentration of concrete constituting concrete structure B, which is separate from concrete structure A, by fluorescent X-ray analysis and potentiometric titration, respectively, and preparing a calibration curve B showing the correspondence between these values, then crushing the concrete particles obtained in the sampling step and determining the chloride ion concentration obtained by fluorescent X-ray analysis from the chloride ion concentration, using the calibration curve B to determine the chloride ion concentration corresponding to that obtained by potentiometric titration, and determining this as the chloride ion concentration inside concrete structure A. This quantitative method is said to provide a way to quantify the chloride ion concentration in concrete structures quickly, accurately, and at low cost. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2023-070985

[0008] While it is conceivable to use the X-ray fluorescence analysis method described above for the quantitative determination of chloride ions to measure harmful substances in agricultural organic materials, which are the analytes of the present invention, unlike analytes whose main components are inorganic materials such as concrete, agricultural organic materials, especially those classified as compost, are primarily composed of elements that make up organic matter and water, such as hydrogen, carbon, nitrogen, and oxygen. These elements relatively reduce the X-ray fluorescence intensity of the elements being measured, which in turn reduces the accuracy of the analysis. Incidentally, elements that make up organic matter and water, such as hydrogen, carbon, nitrogen, and oxygen, are difficult or impossible to detect using X-ray fluorescence analysis. In this specification, the above components and elements are referred to as interfering components. [Overview of the project] [Problems that the invention aims to solve]

[0009] The present invention aims to provide a pretreatment method for agricultural organic materials, a fluorescent X-ray analysis method using the same, and a screening method, which enable the use of fluorescent X-ray analysis, which shortens analysis time, does not require special skills from the analyst, and reduces the financial, temporal, and environmental costs of analysis, in a desirable state for component analysis of agricultural organic materials using wastewater treatment activated precipitates with the above-described background. [Means for solving the problem]

[0010] The aforementioned problems are solved by the pretreatment method for agricultural organic materials according to the present invention, having the configurations described in (1) to (19) below, and by fluorescent X-ray analysis and screening methods using the same. (1) In a pretreatment method for X-ray fluorescence analysis or screening of target elements in agricultural organic materials derived from wastewater treatment activated precipitate produced when wastewater in a target field is treated by the activated sludge method, - A process to reduce the amount of interfering components that reduce the accuracy of X-ray fluorescence analysis of the target element from the organic material. - A grinding step in which the organic material, whose amount of interfering components has been reduced by the interfering component reduction step, is ground into granular material. - A classification process to classify the granular material and reduce its particle size to a predetermined size or smaller. - A step of adding a target element to the granular material that has been reduced to a predetermined particle size or smaller by the classification step, and - A process to homogenize the distribution of the target element by stirring the granular material to which the target element has been added in a specific amount, thereby uniformly distributing the target element within the granular material. A calibration curve sample preparation method is provided which reduces the amount of interfering components, has a particle size of less than or equal to the predetermined particle size, and has a uniform distribution of the target element for measurement, thereby creating a calibration curve sample. Using a portion of this calibration curve sample, the target element is measured using the X-ray fluorescence analyzer used in the actual measurement to obtain the first measurement value, while, Using the aforementioned part or other part of the calibration curve sample, the element to be measured is measured using a reference analyzer with a different measurement principle than that of the X-ray fluorescence analyzer, and a second measurement value is obtained. The first and second measurement values ​​obtained as described above are compared and contrasted, and a calibration curve is determined from their correlation. A pretreatment method characterized by the following: (2) The pretreatment method of (1) wherein the interfering component reduction step is a drying step in which the interfering component, which is moisture, is reduced by a drying treatment and the organic material is dried to a predetermined moisture content range. (3) The pretreatment method of (2) wherein the predetermined moisture content range is 20% or less. (4) The pretreatment method (2) wherein the drying is carried out using a heat source. (5) The pretreatment method of (2) wherein the drying is carried out by air drying with or without the use of auxiliary tools. (6) If the addition of the element to be measured in the aforementioned element addition step is done by adding a liquid dispersion, the granular material to which this liquid dispersion has been added is place The pretreatment method of (1) comprising a drying step of drying to a specified moisture content range. (7) The pretreatment method of (6) wherein the drying step also serves as a step for reducing interfering components. (8) The pretreatment method of (1) wherein the stirring in the step of homogenizing the distribution of the elements to be measured is performed in the tare bag. (9) The pretreatment method of (1) wherein the wastewater treatment activated precipitate is sewage sludge, activated sludge, excess sludge, human waste sludge, digested sludge, or industrial waste sludge. (10) The pretreatment method of (1) wherein the wastewater treatment activated precipitate is sewage sludge containing raw materials for by-product animal and plant fertilizers, activated sludge, excess sludge, human waste sludge, digested sludge, or industrial waste sludge. (11) The pretreatment method of (1) above, wherein the agricultural organic material is compost, fertilizer or soil conditioner. (12) The pretreatment method of (1) above, wherein the classification step is performed using a sieve made of a non-metal, and the mesh size of the sieve is within 0.038 mm to 2 mm. (13) The pretreatment method of (8) above, wherein the tare is made of a non-metal. (14) The pretreatment method according to claim 1, wherein the agricultural organic material is produced by subjecting the drainage treatment activated sediment in the analysis target field to aerobic fermentation treatment. (15) The pretreatment method of (1) above, wherein the agricultural organic material is produced by subjecting the drainage treatment activated sediment in the analysis target field to heat treatment. (16) The pretreatment method of (1) above, wherein the interfering component reduction step is performed by carbonization treatment. (17) The heat treatment is performed by incineration treatment in the pretreatment method of ( 15 ) above. (18) The interfering component reduction step, the pulverization step and the classification step in the standard sample preparation method of the pretreatment method according to any one of (1) to (17) are used for pretreatment, and the standard trial sample is made to have a predetermined moisture content range and a predetermined particle size or less. For a measurement sample containing an agricultural organic material derived from the drainage treatment activated sediment produced when the drainage in the analysis target field is treated by the activated sludge method and having a uniform distribution of contained components by stirring, the fluorescence X-ray analysis method using the fluorescence X-ray analyzer used in the pretreatment method is used to measure the content of the measurement target element contained in the measurement sample, and the actual content is obtained by comparing this measurement value with the calibration curve. A method for measuring the elements contained in agricultural organic materials. (19) The interfering component reduction step, the pulverization step and the classification step in the standard sample preparation method of the pretreatment method according to any one of (1) to (17) are used for pretreatment, and the standard trialA method for screening agricultural organic materials, comprising: screening agricultural organic materials containing the target element by X-ray fluorescence analysis using an X-ray fluorescence analyzer used in the pretreatment method, using a sample for measurement in which the distribution of contained components has been made uniform by stirring, the sample being derived from activated precipitate produced when wastewater from the target field is treated by the activated sludge method, and having a predetermined moisture content range and particle size or less in the material. [Effects of the Invention]

[0011] In the pretreatment method of the present invention, first, the moisture content of commercially available agricultural organic materials is focused on the moisture content, which is a component that particularly reduces the accuracy of X-ray fluorescence analysis, but whose content can be easily controlled. By reducing the moisture content of agricultural organic materials, the accuracy of X-ray fluorescence analysis is improved. This has the effect of improving the analytical accuracy while enjoying the advantages of simple and low-cost X-ray fluorescence analysis. [Brief explanation of the drawing]

[0012] [Figure 1] This is a correlation diagram showing the correlation between cadmium measurements obtained from the same sample using X-ray fluorescence analysis and atomic absorption spectrometry. [Figure 2] This figure shows the calibration curve obtained by an embodiment of the present invention. Embodiment of the Invention

[0013] The following describes a pretreatment method for agricultural organic materials according to embodiments of the present invention, as well as a fluorescence X-ray analysis method and a screening method using the same. First, the aforementioned pretreatment method will be described as a pretreatment method for fluorescent X-ray analysis or screening of target elements in agricultural organic materials derived from wastewater treatment activated precipitate produced when wastewater in the field to be analyzed is treated with the activated sludge method.

[0014] In this specification, the wastewater treatment activated precipitate refers to sewage sludge, activated sludge, excess sludge, human waste sludge, digested sludge, or industrial waste sludge, and may or may not contain raw materials for by-product animal and plant fertilizers. Examples of the aforementioned organic materials for agriculture include compost, fertilizer, or soil conditioner. The elements to be measured include the following: The elements to be measured include regulated heavy metals that are not permitted to be contained in the aforementioned agricultural organic materials, as well as active ingredients that are contained or should be contained. The five regulated heavy metals are chromium (Cr), nickel (Ni), arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb). Furthermore, 12 of the 17 essential plant elements are targeted for measurement as active ingredients. Specifically, these include five of the nine macronutrients: magnesium (Mg), phosphorus (P), sulfur (S), potassium (K), and calcium (Ca), and seven of the eight trace elements: chlorine (Cl), manganese (Mn), iron (Fe), zinc (Zn), copper (Cu), molybdenum (Mo), and nickel (Ni). Here, Ni may be analyzed as a regulated heavy metal or as an active ingredient. While the 12 active ingredients mentioned above are measurable, the remaining five components are difficult or impossible to measure, yet they may act as harmful substances or pose a risk of harm.

[0015] This pretreatment method first involves creating a calibration curve sample in which the amount of interfering components is reduced, the particle size is below a predetermined particle size, and the target element is uniformly distributed, using a calibration curve sample preparation method comprising the following steps.

[0016] In other words, this method for preparing samples for calibration curves is: - A process to reduce the amount of interfering components that reduce the accuracy of X-ray fluorescence analysis of the target element from the organic material. - A grinding step in which the organic material, whose amount of interfering components has been reduced by the interfering component reduction step, is ground into granular material. - A classification process to classify the granular material and reduce its particle size to a predetermined size or smaller. - A step of adding a target element to the granular material that has been reduced to a predetermined particle size or smaller by the classification step, and - A process to homogenize the distribution of the target element by stirring the granular material to which the target element has been added in a specific amount, thereby uniformly distributing the target element within the granular material. A calibration curve sample preparation method is used to create a calibration curve sample in which the amount of interfering components is reduced, the particle size is below a predetermined particle size, and the target element is uniformly distributed.

[0017] The aforementioned interfering components mainly include water, which reduces the distribution density of the target components and elements in the agricultural organic material and thus reduces the intensity of the detected fluorescent X-rays, and components and elements that are difficult or impossible to detect by fluorescent X-ray analysis, i.e., elements with an atomic number of 10 or less in the periodic table. A typical example of these interfering components is water.

[0018] The following explains each of the processes mentioned above. <Process for reducing interfering components> This process of reducing interfering components is carried out by drying, carbonization, and incineration, among other methods. • Drying process This drying process reduces moisture, a typical interfering component, by drying, and dries the organic material to a predetermined moisture content range. The predetermined moisture content is preferably 20% or less. This drying process may include drying using a heat source, or drying by air drying with or without the use of auxiliary tools. As the heat source, a dry heat machine using high-temperature air can be used. The temperature of the high-temperature air is preferably 100 to 110°C. By drying using this dry heat machine, the moisture content of the organic material to be measured can be reduced to almost 0. Furthermore, the dry heat machine using high-temperature air can be replaced with a moisture meter using infrared radiation. Similar to the drying process using the dry heat machine, the moisture content of the organic material being measured can be reduced to almost zero. A desiccant can be used as an aid for air drying. When using a desiccant in this way, it is preferable to seal the organic material to be measured together with the desiccant in a sealed container in order to isolate it from the outside air. • Carbonization and incineration The sample is carbonized or incinerated to reduce it to charcoal or ash. This carbonization or incineration process can easily reduce some of the interfering components other than moisture.

[0019] <Grinding process> Any method may be used for grinding in this grinding process, but for example, a simple alumina mortar and pestle set may be used. This grinding process reduces the organic material to granular material with a particle size of approximately 2 mm or less.

[0020] <Classification process> Any means of classification in this classification process may be used, but for example, a sieve can be used. Preferably, the sieve should be entirely made of non-metallic materials, for example, a frame made of polypropylene, polyester, or polyvinyl chloride, and a mesh made of nylon, PET, carbon, or silk, with an opening of 2 mm or less (currently, the lower limit for commercially available sieves is 0.038 mm). This will reduce the organic material to be measured into granular particles with a particle size of less than 2 mm. It is preferable to use sample particles with the smallest possible particle size. Therefore, the smaller the sieve mesh size, the better, but the smaller the mesh size, the longer the sieving time required. The sieve mesh size can be selected appropriately according to the desired accuracy of the analytical results. In particular, if an approximate result is sufficient, a 2 mm sieve mesh is acceptable.

[0021] <Method for adding elements to be measured> Examples of the elements to be measured, i.e., the elements to be measured, include the active ingredients that agricultural organic materials such as fertilizers should contain, and conversely, the harmful ingredients (regulated ingredients) that should not be contained. Examples of the active ingredients and harmful heavy metals to be measured include these active ingredients and harmful heavy metals. These active ingredients and harmful heavy metals are described above. Some of the substances to be measured mentioned above are commercially available as liquid dispersions (suspensions), so these may be used. When using such liquid dispersions, it is preferable to further include a second interfering component reduction step in which the granular material to which the liquid dispersion is added is dried to within the predetermined moisture content range.

[0022] <Process for homogenizing the distribution of elements to be measured> In this process of homogenizing the distribution of the element to be measured, the granular material to which the element to be measured has been added in a specific amount is stirred to uniformly distribute the element to be measured within the granular material. This prevents uneven measurement. In the aforementioned process of homogenizing the distribution of the elements to be measured, it is preferable to perform the stirring in a non-metallic (plastic) tare bag.

[0023] <Calibration curve creation process> The calibration curve is created using the calibration curve sample prepared as described above, as follows. First, a portion of the sample for the calibration curve is taken, and the element to be measured is measured using a fluorescent X-ray analyzer used for the actual measurement to obtain a first measurement value. Meanwhile, another portion of the sample for the calibration curve, preferably a new portion, is taken, and the element to be measured is measured using a reference analyzer with a different measurement principle than the fluorescent X-ray analyzer, such as an atomic absorption spectrometer, to obtain a second measurement value. Then, the first and second measurement values ​​obtained as described above are compared and compared, and the calibration curve is determined from their correlation.

[0024] <Method for measuring elements contained in agricultural organic materials and method for screening agricultural organic materials> The method for measuring elements contained in agricultural organic materials involves measuring the content of the target element contained in the sample prepared as described above by X-ray fluorescence analysis using the X-ray fluorescence analyzer used in the pretreatment method, and obtaining the actual content by comparing this measured value with the calibration curve. On the other hand, the agricultural organic material screening method involves screening the measurement samples prepared as described above for agricultural organic materials containing the target element. [Examples]

[0025] Basic samples were prepared from compost made from sewage sludge using the procedure described above. Specifically, the compost was dried overnight in a dry heat oven at 100-110°C, its weight was measured, and it was dried again in the same dry heat oven until it reached a constant weight, i.e., no further weight change occurred. This took 1 hour. As a result, the moisture content of the compost was reduced to almost 0. The compost in this state was crushed using an alumina mortar and pestle, and sieved using a non-metallic sieve (with a polypropylene frame and nylon mesh) with a mesh size of 1 mm to obtain the basic sample. In addition, five 10 g samples were taken from the prepared basic sample, and 50 μl, 100 μl, 150 μl, 300 μl, and 500 μl of 1000 mg / l cadmium standard solution were added to each sample as appropriate, and the samples were dried again in the same dry heat oven until a constant weight was reached. The moisture content was measured and found to be almost 0. After the dried material was cooled, it was stirred in a plastic tare bag to ensure uniform dispersion of the components. Through this process, calibration curve samples 1, 2, 3, 4, and 5 with various cadmium concentrations were prepared.

[0026] The five calibration curve samples 1, 2, 3, 4, and 5 were measured using both flame atomic absorption spectrometry and energy-dispersive X-ray fluorescence spectrometry. For measurement using energy-dispersive X-ray fluorescence spectrometry, one side of a cylindrical container was covered with a polymer thin film, and the measurement sample or calibration curve sample was packed tightly into it by tapping to form a loose powder.

[0027] The correlation between the measurement results of flame atomic absorption spectrometry and X-ray fluorescence analysis was investigated for the aforementioned calibration curve sample. This correlation is shown in Figure 1. In this figure, the horizontal axis represents the cadmium concentration measured by flame atomic absorption spectrometry, expressed as milligrams per kilogram of dry weight (mg / kgDS). The vertical axis represents parts per million (ppm), and since dry material was measured, mg / kgDS = ppm. The coefficient of determination (R) is then calculated. 2 The value was a very high 0.995.

[0028] Since the regulatory limit for cadmium is 5 mg / kgDS, a calibration curve (see Figure 2) was created to correct the values ​​measured by X-ray fluorescence analysis to the values ​​measured by flame atomic absorption spectrometry within the range of 2 to 15 mg / kgDS. y = 1.039x - 1.1787 (y: measured value by flame atomic absorption spectrometry, x: measured value by X-ray fluorescence analysis)

[0029] Composts a and b, similar to those collected at different times, were processed in the same manner as the basic samples to become measurement sample A and measurement sample B, respectively. Compost prepared using the same preparation method and cadmium addition as the calibration curve sample was used to create measurement sample C. These three types of measurement samples were measured using a flame atomic absorption spectrometry device and a fluorescence X-ray analysis device (which outputs values ​​calibrated using the calibration curve shown in Figure 2). The measurements obtained by flame atomic absorption spectrometry and the measurements obtained by fluorescence X-ray analysis corrected by the calibration curve were compared. The results are shown in the table below. JPEG0007831890000002.jpg28131

[0030] For sample A, which had a cadmium content of 2.3 mg / kgDS as measured by flame atomic absorption spectrometry, the cadmium content by X-ray fluorescence analysis after correction with a calibration curve was 2 ± 0.7 ppm. Since the detection limit of the X-ray fluorescence analyzer used for sample B was 2 ppm, the cadmium content obtained by flame atomic absorption spectrometry was 1.9 mg / kgDS, and the cadmium content obtained by X-ray fluorescence analysis after correction with a calibration curve was below the detection limit. For sample C, which had a cadmium content of 6.81 mg / kgDS as measured by flame atomic absorption spectrometry, the cadmium content by X-ray fluorescence analysis after correction with a calibration curve was 7 ± 0.8 ppm. In all cases, the values ​​were very close to those obtained by flame atomic absorption spectrometry. This study focuses on a single element, Cd, but depending on the type and number of elements being measured, it is possible to simultaneously perform quantitative analysis or screening of multiple elements, or quantitative analysis or screening of specific elements, by appropriately selecting the model of X-ray fluorescence analyzer used. For example, if the goal is to measure multiple elements simultaneously, it is best to use an energy-dispersive type analyzer (such as the VANTA series from Evident Corporation, the X-MET8000 series from Hitachi High-Tech Corporation, the Niton series from Thermo Fisher Scientific, the Tracer5 series from Bruker, the EA1400 from Hitachi High-Tech Corporation, or the JSX-1000 series from JEOL Ltd.). On the other hand, if the goal is to measure specific trace elements with higher resolution, it is recommended to use a wavelength-dispersive type analyzer (such as the ZSX PRIMUS series from Rigaku Holdings Corporation, the Zetium from Malvern Panalytical Division of Spectris Corporation, or the MFX-2400 from Shimadzu Corporation).

[0031] Based on the above, this disclosure can be said to be suitable for component analysis or screening of the said agricultural organic material.

Claims

1. In a pretreatment method for X-ray fluorescence analysis or screening of target elements in agricultural organic materials derived from wastewater treatment activated precipitate produced when wastewater in the target field is treated by the activated sludge method, - A process to reduce the amount of interfering components that reduce the accuracy of X-ray fluorescence analysis of the target element from the organic material. - A grinding step in which the organic material, whose amount of interfering components has been reduced by the interfering component reduction step, is ground into granular material. - A classification process to classify the granular material and reduce its particle size to a predetermined size or smaller. - A step of adding a target element to the granular material that has been reduced to a predetermined particle size or smaller by the classification step, and - A step to homogenize the distribution of the target element by stirring the granular material to which the target element has been added in a specific amount, thereby uniformly distributing the target element within the granular material. A calibration curve sample preparation method is provided which reduces the amount of interfering components, has a particle size of less than or equal to the predetermined particle size, and has a uniform distribution of the elements to be measured, thereby creating a calibration curve sample. Using a portion of this calibration curve sample, the target element is measured using the X-ray fluorescence analyzer used in the actual measurement to obtain the first measurement value, while, Using one or more of the aforementioned calibration curve sample, the element to be measured is measured using a reference analyzer with a different measurement principle than that of the X-ray fluorescence analyzer to obtain a second measurement value, and then The first and second measurement values ​​obtained as described above are compared and contrasted, and a calibration curve is determined from their correlation. A pretreatment method characterized by the following:

2. The pretreatment method according to claim 1, wherein the interfering component reduction step is a drying step of reducing the moisture, which is the interfering component, by drying and drying the organic material to a predetermined moisture content range.

3. The pretreatment method of claim 2, wherein the predetermined moisture content range is 20% or less.

4. The pretreatment method of claim 2, wherein the drying is performed using a heat source.

5. The pretreatment method of claim 2, wherein the drying is performed by air drying with or without the use of auxiliary tools.

6. The pretreatment method according to claim 1, further comprising a drying step of drying the granular material to which the liquid dispersion has been added within a predetermined moisture content range, in the case where the addition of the element to be measured in the element to be measured step is by means of a liquid dispersion.

7. The pretreatment method of claim 6, wherein the drying step also serves as a step for reducing interfering components.

8. The pretreatment method according to claim 1, wherein the stirring in the step of homogenizing the distribution of the element to be measured is performed in the tare bag.

9. The pretreatment method according to claim 1, wherein the wastewater treatment activated precipitate is sewage sludge, activated sludge, excess sludge, human waste sludge, digested sludge, or industrial waste sludge.

10. The pretreatment method of claim 1, wherein the wastewater treatment activated precipitate is sewage sludge containing raw materials for by-product animal and plant fertilizers, activated sludge, excess sludge, human waste sludge, digested sludge, or industrial waste sludge.

11. The pretreatment method according to claim 1, wherein the agricultural organic material is compost, fertilizer, or soil conditioner.

12. The pretreatment method of claim 1, wherein the classification step is performed using a non-metallic sieve, and the mesh size of the sieve is between 0.038 mm and 2 mm.

13. The pretreatment method of claim 8, wherein the tare is made of nonmetallic material.

14. The pretreatment method of claim 1, wherein the aforementioned agricultural organic material is produced by aerobic fermentation treatment of wastewater treatment activated precipitate in the field to be analyzed.

15. The pretreatment method of claim 1, wherein the aforementioned agricultural organic material is produced by heat-treating the activated precipitate from wastewater treatment in the field to be analyzed.

16. The pretreatment method according to claim 1, wherein the interfering component reduction step is performed by carbonization treatment.

17. The pretreatment method of claim 15, wherein the heat treatment is performed by incineration.

18. A method for measuring elements contained in agricultural organic materials, wherein the agricultural organic material is pretreated by the interfering component reduction step, crushing step and classification step in the standard sample preparation method of the pretreatment method described in any one of claims 1 to 17, and is below a predetermined moisture content range and predetermined particle size range in the standard sample, and the content of the target element contained in the measurement sample is measured by X-ray fluorescence analysis using the X-ray fluorescence analyzer used in the pretreatment method, and the actual content is obtained by comparing this measured value with the calibration curve.

19. A method for screening agricultural organic materials, wherein agricultural organic materials derived from wastewater treatment activated precipitate produced when wastewater from the target field is treated by the activated sludge method are pretreated by the interfering component reduction step, crushing step and classification step in the standard sample preparation method of the pretreatment method according to any one of claims 1 to 17, and the distribution of contained components is made uniform by stirring of the sample, and the agricultural organic materials containing the target element are screened by X-ray fluorescence analysis using the X-ray fluorescence analyzer used in the pretreatment method.

Images