Chaotic sample identification and screening method based on filter material use cycle determination and application

Abstract

The invention relates to a chaos sample recognition and screening method based on filter material use cycle determination and application, and relates to the technical field of water treatment. The invention relates to a chaos sample identification and screening method based on filter material use cycle determination. The method comprises the following steps: (1) processing a sampling sample to be sampled; and (2) carrying out sampling inspection on the sampling inspection sample. According to the invention, through strong magnetic attraction, or / and colored resin, or / and particle size, sampling inspection samples can be rapidly identified and screened in 1-4 billion common filter materials in a large-scale denitrification biofilter; according to the method, biochemical consumption, which is one of important indexes for evaluating the service cycle of the pyrite filter material, is considered, and meanwhile, in the same operation environment, the detection of the wear value and the crushing value is more accurate than that of a recommended method of a filter material standard (CJ / T 43-2005) for water treatment.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, and in particular to an identification and screening method for chaotic samples based on the determination of filter material use cycle and an application thereof. Background Art

[0002] In the process of evaluating the durability and service life of filter media, the wear rate and breakage rate of filter media are important indicators of filter media performance. Among them, the wear rate refers to the proportion of filter media peeling off or breaking due to friction and wear during backwashing and filtration, and the breakage rate refers to the proportion of filter media destroyed during use due to external force or the force of the filter medium. When the wear rate and breakage rate of filter media are too large, the filtration effect will deteriorate, the filtration speed will slow down, and the service life of the filter media will be shortened. The sum of the wear rate and breakage rate of quartz sand filter media in the standard for filter media for water treatment (CJ / T 43-2005) should not be greater than 1.5% (by mass).

[0003] The Mohs hardness of pyrite granular filter material is 6.0-6.5; the patent with publication number CN117430296 shows that it has good wear resistance, so it has the filtration performance of intercepting SS suspended solids similar to quartz sand. Intermittent gas-water backwashing will cause wear and breakage of pyrite granular filter material. At the same time, since the autotrophic denitrification mediated by pyrite is a dual-path synergistic action of "biologically driven denitrification-non-biological chemical phosphorus removal" to achieve the simultaneous removal of nitrogen and phosphorus; therefore, the pyrite granular filter material will produce a certain amount of biochemical consumption, which is one of the important indicators for evaluating the service life of pyrite filter material in addition to the wear rate and breakage rate. Up to now, the standard for filter material for water treatment (CJ / T 43-2005) only describes the determination method of filter material wear rate and breakage rate, and no relevant literature has been found to comprehensively and systematically standardize and explain the biochemical consumption rate for the determination of the service life of pyrite filter material.

[0004] In addition, the following problems exist in the process of evaluating the durability and service life of filter media: (1) The determination method of filter media wear rate and breakage rate in the water treatment filter media standard (CJ / T 43-2005) is a dry simulation method, which has great limitations and fails to truly express the actual state of the filter media during filtration, air-water backwashing, and static standing. Therefore, the estimated service life error is large. (2) In the process of random sampling of filter media, due to the large area of ​​the filter pool, there are about 10 million equal-circle particles with a particle size of 2-3 mm in each cubic meter of filter media. When combined air-water backwashing is used, as long as the flushing water flow rate reaches 40-50% of the minimum fluidized flushing flow rate, strong stirring and circulation effects will be generated in the filter bed. The entire filter bed will be disturbed at the beginning of flushing. In the airflow vortex area formed when the bubbles rise, the rolling of the filter material will cause violent collision and friction between the filter material particles. At this time, about 3 to 10 billion filter material particles in the filter tank are in a chaotic state, and the movement trajectory of the filter material random inspection samples is difficult to track and identify. In addition, when the filter tank outlet weir is too low, the filter material will produce sand running, which makes it impossible to maintain continuity and scientificity in the total value detection data of the filter material mass loss. In view of the above problems, the present invention provides a chaotic sample identification and screening method based on the determination of the filter material use cycle and its application. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a method and application for identifying and screening chaotic samples based on the determination of filter material use cycle. The purpose is to realize the rapid identification and screening of random inspection samples of filter material particles in the chaotic motion state in the denitrification biological filter, weigh the random inspection samples of filter material according to a fixed period during operation, and fit the change curve of the mass loss of random inspection samples of filter material by systematic random sampling, so as to accurately determine the use cycle of the filter material.

[0006] The technical solution of the present invention to solve the above technical problems is as follows: In the first aspect, a method for identifying and screening chaotic samples based on the determination of the filter material use cycle comprises the following steps: (1) Processing of samples to be inspected: Get the maximum particle size of the filter material to be tested ; Make the particle size of the sample to be processed The maximum particle size of the filter material to be tested 1.0~1.1 times of the weight of the sample to be processed; drilling the sample to be processed to obtain a drilled sample, the drilled sample and the filter material to be tested have the same reaction specific surface area; inserting a magnetic metal segment into the pores of the drilled sample, and sealing and covering the two ends of the pores of the drilled sample with colored resin to obtain a marked sample; taking the lowest weight of a single marked sample as the reference weight, making the weight of all the marked samples equal to the reference weight, and obtaining the sample to be tested; (2) Random inspection of samples: The samples to be inspected are placed into the filter tank, so that the samples to be inspected and the filter material to be inspected are operated in the same environment; according to the sampling period, through strong magnetic attraction, and / or colored resin, and / or particle size, when the air-water backwashing intensity peaks and the filter layer particles are in an expanded and suspended state, the samples to be inspected are randomly inspected to obtain the inspection samples.

[0007] The present invention strictly limits the fixed multiple relationship between the random inspection sample of the drilling hole and the diameter of the filter material to be inspected through a composite volume derivation formula to ensure that the two have the same reaction specific surface area.

[0008] The beneficial effects of the present invention are: (1) The chaotic sample identification and screening method based on the determination of the filter material use cycle of the present invention can quickly identify and screen random samples from 1 to 4 billion ordinary filter materials in a large-scale denitrification biological filter tank through strong magnetic attraction and / or colored resin and / or particle size.

[0009] (2) When the present invention uses pyrite filter material as a test filter material, the biochemical consumption, one of the important indicators for the use cycle evaluation, is taken into consideration. At the same time, the same operating environment makes the wear value and breakage value detection more accurate than the method recommended by the water treatment filter material standard (CJ / T43-2005).

[0010] (3) In the later stage of operation, the density and area differences between the random inspection samples and ordinary particles are small, and large-scale stratification will not occur. The probability of all random inspection samples being distributed in the aerobic zone and the anaerobic zone is normally distributed. Therefore, there is no need to collect random inspection samples in layers, which reduces the difficulty of sampling.

[0011] (4) In the method for identifying and screening chaotic samples based on the determination of the filter material use cycle of the present invention, the initial weight of the filter material random inspection samples is a uniform weight, which is convenient for subsequent statistical induction, and the random sampling method adopted ensures the scientific nature of the data.

[0012] Based on the above technical solution, the present invention can also be improved as follows.

[0013] Furthermore, the processing of the sample to be sampled in step (1) includes the following specific steps: (1-1) Collect the particle size range of the filter material to be tested and obtain the maximum particle size of the filter material to be tested ; Make the particle size of the sample to be processed The maximum particle size of the filter material to be tested 1.0~1.1 times of the particle size of the sample to be processed , obtaining the drilling diameter of the sample to be processed; (1-2) drilling the sample to be processed according to the drilling diameter of the sample to be processed to obtain a drilled sample, wherein the drilled sample has the same reaction specific surface area as the filter material to be tested; inserting a magnetic metal segment into the pores of the drilled sample, and sealing and covering both ends of the pores of the drilled sample with a colored resin to obtain a marked sample; (1-3) The marked samples are uniformly weighed, and the lowest weight of a single marked sample is used as the reference weight. The marked samples that exceed the reference weight are ground with a grinding wheel so that the weight of all the marked samples is equal to the reference weight, thereby obtaining the samples to be inspected.

[0014] The beneficial effect of adopting the above further scheme is: by enhancing the magnetism of the sample for sampling, or / and using colored resin to mark the sample, or / and appropriately increasing the particle size of the sample for sampling, etc., the sample for sampling can be quickly collected in a chaotic state after intense movement such as air-water backwashing; In addition, a benchmark weight for random inspection samples is established, and the initial weight is a uniform weight, which is convenient for subsequent statistical induction and ensures the scientific nature of continuous random sampling data.

[0015] Furthermore, the specific method for obtaining the drilling diameter of the sample to be processed in step (1-1) is as follows: the drilling diameter of the sample to be processed is calculated by the following formula (1); formula (1) is as follows: (1); In formula (1) is the particle size of the sample to be processed, N is the diameter of the drill hole of the sample to be processed, and the value range of N is 1.0~1.1.

[0016] The beneficial effect of adopting the above further scheme is that the particle size of the filter material random inspection samples is larger than that of ordinary filter material particles, but does not exceed 10% of the maximum particle size of ordinary filter material, thereby preventing the particle size difference of the subsequent random inspection samples from being too large, and preventing stratification due to the different water-facing areas of the particles during the air-water backwashing process.

[0017] Furthermore, the magnetic metal segment in step (1-2) comprises an alloy of one or at least two of iron, nickel, and cobalt; the diameter of the magnetic metal segment is not greater than the borehole diameter of the sample to be processed, and the length of the magnetic metal segment is less than the borehole length of the sample to be processed; further, the length of the magnetic metal segment is about half of the borehole length of the sample to be processed; The colored resin in step (1-2) includes at least one of colored epoxy resin, alkyd resin, phenolic resin and polyurethane resin, and the amount of the colored resin used is half of the drilling length.

[0018] The beneficial effect of adopting the above further scheme is that the average density of the magnetic metal segment and the colored resin is approximately equal to the density of the pyrite particles, and the density difference between the random inspection samples and the ordinary inspection filter material is controlled to be less than 5%. In the later operation, the random inspection samples will run through the layers due to the huge difference in particle density. Therefore, there is no need to collect the random inspection samples in layers, which greatly reduces the difficulty of sampling.

[0019] Furthermore, the random inspection of the samples in step (2) includes the following specific steps: (2-1) placing the sample to be inspected into a specific range of the filter layer of the filter tank, so that the sample to be inspected and the filter material to be inspected are operated in the same environment; (2-2) According to the sampling period, the sample to be inspected is randomly selected within the specific range by strong magnetic attraction, and / or colored resin, and / or particle size, when the filter layer particles are in an expanded and suspended state at the peak of the air-water backwash intensity, to obtain the sample to be inspected.

[0020] The beneficial effects of adopting the above further scheme are: under the same operating environment, the wear value and breakage value detection are more accurate than the method recommended by the standard for filter media for water treatment (CJ / T 43-2005); when pyrite filter media is used as a backup filter media, the biochemical consumption, one of the important indicators for evaluating the filter media service life, is fully considered.

[0021] Furthermore, in step (2-1), the specific range of the filter layer of the filter tank is obtained by a perforated enclosure; the side length of the perforated enclosure is 1.2m~2m, and the height of the perforated enclosure exceeds the filter tank flooding by more than 20 cm.

[0022] The beneficial effects of adopting the above further solution are: reducing the movement area through the perforated enclosure, narrowing the scope of random inspection, and reducing the 30-100 billion ordinary filter particles in the large denitrifying biological filter to 30 million particles.

[0023] Furthermore, in step (2-2), the sampling period interval is at least 10 days, and at least 50 consecutive periods are taken to ensure the representativeness of the sample data.

[0024] The beneficial effect of adopting the above further scheme is that the sampling method is highly random, can break through the limitations of subjectivity and stereotypes, and randomly and evenly select samples from many samples in the filter pool with a wide coverage, greatly improving the probability of obtaining diverse samples.

[0025] In the second aspect, the random sampling samples obtained by the chaotic sample identification and screening method based on the determination of the filter material use period are applied in the construction of a use period determination model for the filter material to be tested.

[0026] The beneficial effect of adopting the above scheme is that by constructing the model of the present invention, the biochemical consumption, which is one of the important indicators for evaluating the service life of pyrite filter media, is taken into consideration. At the same time, under the same operating environment, the wear value and breakage value detection are more accurate than the method recommended by the water treatment filter media standard (CJ / T 43-2005).

[0027] In the third aspect, a method for constructing a model for determining the service life of a filter material comprises the following steps: recording the quality data of each sampling period of a sample sampled according to the chaotic sample identification and screening method based on the determination of the service life of a filter material, and fitting a mass loss curve; and determining the service life of the filter material to be inspected based on the fitted mass loss curve.

[0028] Furthermore, when the filter material to be tested is pyrite filter material, the equation of the mass loss curve is shown in formula (2): (2); In formula (2), x is the filter material use cycle; y is the mass of pyrite filter material corresponding to a certain cycle; When the filter material to be tested is quartz sand filter material, the equation of the mass loss curve is shown in formula (3): (3); In formula (3), x is the filter media usage cycle; y is the mass of quartz sand filter media corresponding to a certain cycle.

[0029] The beneficial effect of adopting the above further scheme is that the linear equation fitted by the model building method of the present invention can be used to scientifically display the quality loss changes of the sampled samples and predict the use cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a schematic diagram of the structural arrangement of the filter layer, the supporting layer and the filter bottom plate in the filter tank of the present invention.

[0031] Figure 2It is a schematic diagram of the arrangement of the perforated stainless steel enclosure in the filter tank of the present invention.

[0032] Figure 3 It is a schematic diagram of the connection of the upper and lower perforated stainless steel enclosures of the present invention.

[0033] Figure 4 The present invention is an assembly diagram of a stainless steel enclosure with holes in the filter tank and the filter tank.

[0034] Figure 5 It is a comparison chart of the particle sizes of the common filter material of the present invention and the sample for random inspection.

[0035] Figure 6 This is a comparison chart of the wear and breakage prediction and biochemical consumption prediction curves of the sample sampled in the present invention.

[0036] Figure 7 This is a comparison chart of the wear and breakage curves of the samples randomly inspected in the present invention.

[0037] Figure 8 This is a wear and breakage curve diagram of the quartz sand sample sample of the present invention.

[0038] Fig. 9 This is a wear and breakage prediction curve of the quartz sand random inspection sample of the present invention. DETAILED DESCRIPTION

[0039] The principles and features of the present invention are described below, and the examples are only used to explain the present invention and are not used to limit the scope of the present invention. If no specific technology or conditions are specified in the embodiments, the technology or conditions described in the literature in this field or the product instructions are used. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased through regular channels.

[0040] This embodiment relates to a method for identifying and screening chaotic samples based on the determination of filter material use cycle, comprising the following steps: (1) Processing of samples to be inspected: Get the maximum particle size of the filter material to be tested ; Make the particle size of the sample to be processed The maximum particle size of the filter material to be tested 1.0~1.1 times of the weight of the sample to be processed; drilling the sample to be processed to obtain a drilled sample, the drilled sample and the filter material to be tested have the same reaction specific surface area; inserting a magnetic metal segment into the pores of the drilled sample, and sealing and covering the two ends of the pores of the drilled sample with a colored resin to obtain a marked sample; taking the lowest weight of a single marked sample as the reference weight, making the weight of all the marked samples equal to the reference weight, and obtaining the sample to be tested; In this embodiment, the processing of the sample to be sampled in step (1) preferably includes the following specific steps: (1-1) Collect the particle size range of the filter material to be tested and obtain the maximum particle size of the filter material to be tested ; Make the particle size of the sample to be processed The maximum particle size of the filter material to be tested 1.0~1.1 times of the particle size of the sample to be processed , obtaining the drilling diameter of the sample to be processed; (1-2) drilling the sample to be processed according to the drilling diameter of the sample to be processed to obtain a drilled sample, wherein the drilled sample has the same reaction specific surface area as the filter material to be tested; inserting a magnetic metal segment into the pores of the drilled sample, and sealing and covering both ends of the pores of the drilled sample with a colored resin to obtain a marked sample; (1-3) The marked samples are uniformly weighed, and the lowest weight of a single marked sample is used as the reference weight. The marked samples that exceed the reference weight are ground, for example, using a grinding wheel, so that the weight of all the marked samples is equal to the reference weight, thereby obtaining the samples to be inspected.

[0041] Specifically, in this embodiment, the specific method of obtaining the drilling diameter of the sample to be processed in step (1-1) is as follows: the drilling diameter of the sample to be processed is calculated by the following formula (1); formula (1) is as follows: (1); In formula (1) is the particle size of the sample to be processed, is the drilling diameter of the sample to be processed, and the value range of N is 1.0~1.1, for example, 1.01, 1.03, 1.06, 1.07, 1.08, 1.1 and so on.

[0042] Specifically, in this embodiment, the magnetic metal segment in step (1-2) includes an alloy of one or at least two of iron, nickel, and cobalt; the diameter of the magnetic metal segment is not greater than the borehole diameter of the sample to be processed, and the length of the magnetic metal segment is less than the borehole length of the sample to be processed; specifically, the length of the magnetic metal segment is half the borehole length of the sample to be processed; The colored resin in step (1-2) includes at least one of colored epoxy resin, alkyd resin, phenolic resin and polyurethane resin; specifically, the colored resin is half the length of the drilling hole.

[0043] In order to identify and screen the random inspection samples of filter material particles in the chaotic motion state in the denitrification biological filter, the random inspection samples were drilled, and magnetic metal segments, such as iron wire segments, were inserted into the channels. The two ends of the channels were sealed and covered with colored resins (such as red aerobic resin seals). In the later sampling process, simple tools such as strong magnets were used to insert the filter material particle layer during the gas-water backwashing process and carry out the random inspection samples. In a static state, the samples can be quickly collected through the colored resin color mark. Among them, the amount of magnetic metal segments and epoxy resin can be set in different volumes according to the density of heavy-density ore filter material (pyrite filter material), so that the average density of the magnetic metal segments and epoxy resin is close to that of the heavy-density ore filter material, preventing the random inspection samples from running due to the huge difference in particle density.

[0044] Although magnetic identification can be increased by installing a magnetic metal segment inside the sample for sampling, and image identification can be increased by covering the outer surface with colored epoxy resin, the portion of the outer surface of the sample for sampling covered with colored epoxy resin does not produce biochemical consumption, in order to avoid a significant difference in the biochemical consumption rate between the filter material and the sample for sampling with the same particle size and surface area. The present invention increases the particle size of the sample for sampling so that the surface area of ​​the pyrite that produces biochemical consumption (excluding the portion covered with colored epoxy resin) is substantially equal to that of the filter material in the filter tank, and increasing the particle size of the sample for sampling also further increases the sieve recognition of the sample for sampling.

[0045] like Figure 5 As shown, the specific surface area of ​​the initial filter material sphere is , the diameter is . Assume that the specific surface area of ​​the filter material sample sphere is , the diameter is ; The diameter of the marking hole of the sample sphere is , the specific surface area of ​​the spherical caps on both sides of the marked hole is ; When the specific surface area of ​​the sample after deducting the pore crown ( - ) and the specific surface area of ​​pyrite filter media spheres When the values ​​are equal, the maximum particle size of the filter media is Particle size of sample And the diameter of the ball marking hole The relationship is as follows: (4); Particle size of general sampling samples The maximum particle size of the filter media 1.0~1.1 times of the diameter of the sample sphere With marked hole diameter The relationship is as follows: (1); In addition, all samples randomly inspected are weighed uniformly, and the lowest weight of a single particle is selected as the basis. Other overweight particles are ground with a grinding wheel to ensure that all samples randomly inspected maintain a uniform weight.

[0046] (2) Random inspection of samples: The sample to be sampled is placed in the filter tank ( Figure 1 ), so that the sample to be inspected and the filter material to be inspected are operated in the same environment; according to the sampling cycle, through strong magnetic attraction, and / or colored resin, and / or particle size, at the peak of the air-water backwashing intensity, the filter layer particles are in an expanded and suspended state, and the sample to be inspected is randomly inspected to obtain the sample.

[0047] In this embodiment, the sampling of samples in step (2) preferably includes the following specific steps: (2-1) When the denitrification biofilter is backwashing, the sample to be sampled is placed within a specific range of a certain filter layer at a certain height of the filter. Figure 4 ), so that the sample to be inspected and the filter material to be inspected are operated in the same environment; (2-2) According to the sampling period, the sample to be inspected is randomly sampled within the specific range by strong magnetic attraction, or / and colored resin, or / and particle size to obtain the sample.

[0048] Preferably, in the present embodiment, the specific range of the filter layer of the filter tank in step (2-1) is obtained by a perforated enclosure; the side length of the perforated enclosure is 1.2m~2m, and the height of the perforated enclosure exceeds the filter tank flooding by more than 20 cm.

[0049] To ensure that the sample samples and ordinary filter media particles operate in the same environment, specifically, in the denitrifying biological filter, about 50 cm away from the side wall of the filter, a perforated 304 stainless steel plate enclosure is used to limit the area of ​​any area to 2m×2m. The air-water backwash arranged at the bottom of the area produces basically the same degree of collision and wear on the filter media particles. The setting of micropores ensures the continuous circulation of sewage inside and outside the enclosure, produces biochemical effects on the particles, and prevents the sample samples of the filter media from leaking out of the enclosure.

[0050] Among them, the perforated 304 stainless steel plate enclosure is divided into a perforated upper enclosure and a perforated lower enclosure. The upper enclosure and the lower enclosure are connected by flanges 30cm above the surface of the filter layer. The bottom of the lower enclosure is fixed to the bottom plate of the filter tank with bolts. The top of the upper enclosure is 20cm higher than the flooding ( Figure 2 and 3 ).

[0051] Specifically, in step (2-2), the sampling interval is at least 10 days, and the continuous sampling is at least 50 cycles. For example, the sampling interval is 15 days, and the continuous sampling is 50 cycles, etc.; This embodiment also involves using the sample samples sampled by the chaotic sample identification and screening method based on the filter material use period determination to construct a model for the filter material use period determination.

[0052] The present embodiment also relates to a method for constructing a model for determining the service life of a filter material, comprising the following steps: recording the quality data of each sampling period of the sample to be inspected, and fitting a mass loss curve according to the mass change; and determining and predicting the service life of the filter material to be inspected based on the fitted mass loss curve.

[0053] Specifically, in this embodiment, after all the sampled samples are weighed uniformly, a certain number of filter material particles are randomly sampled from the filter pool at a fixed period (T = 10 days) as samples, and 50 consecutive cycles are taken. The quality data of the sampled samples in each cycle are recorded. In order to scientifically reflect the trend and law of the loss of filter material quality, a linear function relationship between the quality of the sampled samples and the sampling period T is constructed as follows: (5); In formula (5), M sam is the mass of the sample, K is the change rate of the wear and breakage curve, T is the reaction period of the sample, and b is the initial maximum mass value of the sample.

[0054] When the filter material to be tested is pyrite filter material, the mass loss curve equation is shown in formula (2): (2); In formula (2), x is the filter material usage cycle; y is the mass of pyrite filter material corresponding to a certain cycle.

[0055] When the filter material to be tested is quartz sand filter material, the obtained quartz sand filter material mass loss curve equation is shown in formula (3): (3); In formula (3), x is the filter media usage cycle; y is the mass of quartz sand filter media corresponding to a certain cycle.

[0056] In summary, the chaotic sample identification and screening method based on the determination of the filter material use cycle of the present invention can quickly identify and screen random samples in a large-scale denitrifying biological filter (1 to 4 billion ordinary filter materials) through strong magnetic attraction, and / or colored resin, and / or particle size.

[0057] According to the chaotic sample identification and screening method based on the determination of the filter material use cycle of the present invention, the density difference between the random inspection sample and the common filter material for inspection is less than 5%. In the later operation, the random inspection samples may be scattered due to the huge difference in particle density. Therefore, there is no need to collect the random inspection samples in layers, which greatly reduces the sampling difficulty.

[0058] The chaotic sample identification and screening method based on the determination of the filter material use cycle of the present invention unifies the initial weight of the sample for random inspection, which is convenient for later statistical induction, and the adopted random sampling method ensures the scientificity and extensiveness of the data.

[0059] When the model of the present invention is constructed, the biochemical consumption, which is one of the important indicators for evaluating the service life of pyrite filter media, is taken into consideration, and the operating environment makes the wear value and breakage value detection more accurate than the method recommended by the water treatment filter media standard (CJ / T 43-2005). The following is an explanation with specific embodiments.

[0060] Example 1: The particle size of the random inspection sample of filter material with a particle size of 2-3 mm and the diameter of its marked hole are determined.

[0061] Assume that the maximum particle size specific surface area of ​​pyrite filter material with a particle size range of 2~3mm is The maximum particle size is ; The specific surface area of ​​the sample sphere is , the diameter is ; The diameter of the marking hole of the sample sphere is , the specific surface area of ​​the spherical caps on both sides of the marked hole is When the specific surface area of ​​the sample after deducting the pore crown ( - ) and the maximum particle size specific surface area of ​​pyrite filter media spheres When the values ​​are equal, the maximum particle size of the common filter media in the filter tank is Particle size of sample And the diameter of the ball marking hole The relationship is shown in formula (4), which can be derived as follows.

[0062] The specific surface area of ​​the sample after deducting the pore crown and the specific surface area of ​​the pyrite filter material sphere satisfy the following relationship (6): (6); According to the formula of sphere specific surface area and spherical crown area, the calculation formula of the specific surface area of ​​the sample, the initial pyrite filter material sphere and the spherical crown on both sides of the marked hole is determined, and substituted into formula (6), formula (7) can be obtained: (7); Eliminate the same terms on both sides of equation (7) and remove the denominator to obtain equation (8): (8); To make it more intuitive, we can move the terms in equation (8) to and , The quantitative relationship between them can finally be obtained as formula (4).

[0063] Particle size of general sampling samples is the average particle size of filter media N (1.0~1.1) times, that is and The relationship is: (9); Substituting equation (9) into equation (4), we can get and The derivation process of equation (1) is as follows: Substituting various numerical values ​​and simplifying, we can get formula (10): (10); Eliminate the square root of equation (10) and increase the order of the unknown numbers on both sides to obtain equation (11): (11); Remove the denominator and move the terms in equation (11) to get equation (12): (12); Combining similar terms in formula (12), we can get formula (13): (13); By shifting the terms in equation (13), we can intuitively see and The relationship between them is fixed, and the multiple relationship of N is limited, and finally formula (1) is obtained.

[0064] The initial pyrite filter ball diameter in this example If the diameter of the sample sphere is 3.00 mm, The diameters are distributed as shown in Table 1. During the test, a specific value of a multiple relationship is selected, and a spherical drill is used to perform precision hole marking on the initial pyrite sphere. At this time, a hollow slot structure can be generated in the cavity of the sample sphere. The diameter of the marked hole is calculated using the surface area composite derivation diameter relationship formula (1), and the relevant data are recorded as shown in Table 1. The corresponding value is the precise diameter of the marked hole of the sample sphere at this multiple relationship.

[0065] Table 1 Relationship between filter material sphere diameter multiples under different multiples Example 2: Determination of the usage cycle of pyrite random samples.

[0066] This embodiment adopts a downward flow denitrification biofilter, uses pyrite as the filter material, the inlet COD concentration is 50.1 mg / L, pH <7, the outlet total nitrogen is <10 mg / L, the air flushing time is 5 min, the intensity is ≤27.78 L / (m 2 ·s), water flushing time is 10 min, intensity is ≤4.17 L / (m 2 ·s), air-water combined flushing time is 8 min, intensity ≤15.5 L / (m 2 ·s), and the outlet water filtration rate is 6 m / h.

[0067] (1) Data preparation and collection: Step ①: To keep all the samples uniform in weight, use formula (14) to calculate Standard quality. According to the physical and chemical properties of pyrite, The density of pyrite is usually 5.0g / m 3 , so the initial sample mass is calculated to be 0.75g.

[0068] (14); (15); Step ②: According to the above sampling method, a certain number of filter particles are extracted from the filter tank as samples at a fixed period (T=10 days) for 50 consecutive cycles.

[0069] Step ③: Record relevant data such as the quality of the extracted samples.

[0070] (2) Data analysis: Step ①: Conduct statistical analysis on the collected quality data and eliminate the samples with large deviation values.

[0071] Step ②: Analyze the relationship between sample quality and sampling period to understand the trend and law of filter material quality loss.

[0072] (3) Establish a prediction model: Build sample quality , the linear function relationship of the sampling period T, is initially proposed as the following one-variable linear equation (5): (5); Based on the actual operation of the filter, in this equation As the period T increases, regular changes should gradually occur, showing a monotonically decreasing trend. According to the sampled samples, a linear equation group between the quality change and the filter material use period can be fitted, and the model fitting degree R can be calculated. 2 , if R 2>0.7, indicating a higher linear fitting effect, indicating that the equation can be used to show the changing law of sample mass loss.

[0073] When pyrite is used as an electron donor, according to the total denitrification reaction equation of pyrite (16): (16); When the filter water flow rate =6m / h, when the initial nitrate nitrogen concentration is 10mg / L, the theoretical consumption of NO3 in one year - The quality of is as shown in formula (17): (17); According to formula (16), the ratio relationship between FeS2 and NO3 can be obtained, and then the theoretical mass of FeS2 consumed in one year can be determined, as shown in formula (18): (18); The total mass of FeS2 in the theoretical filter is shown in formula (19): (19); Theoretically, the time required for complete consumption of FeS2 is as shown in formula (20): (20); Based on the theoretical consumption cycle of the filter material (27 years), the theoretical prediction line of the mass loss value can be inferred, as shown in formula (21): (twenty one); Substituting the values ​​into equation (22), we can get the fitting degree R 2 =1.0000 (twenty two); According to the equation fitted by the sample values ​​in this experiment, the straight line fitting degree R 2 =0.8289, as shown in formula (2): (2); The actual fitting equation is used to predict the quality change of the sample inspection (i.e., the change trend of the equation is extended until the quality loss reaches 0), as shown in formula (23): (twenty three); Compared with formula (2), the straight line fit R 2 =0.9332, R 2 The fitting effect tends to higher values, indicating that the equation is more reliable and scientific in predicting the long-term quality change trend of the sampled samples.

[0074] like Figure 6 As shown, equations (22) and (23) are intuitively displayed in a unified layer. The biochemical consumption prediction curve for the sample quality shows that it takes 27 years for the sample quality to finally approach 0g. As for the wear and breakage prediction curve, it takes about 12 years for the sample quality to approach 0g. The filter material service life is shorter than the biochemical consumption prediction cycle. The reason is that in actual conditions, the sample will be affected by various factors such as temperature, pH, influent water quality, backwashing intensity, etc. in the filter tank, which will cause the quality loss to be higher than the theoretical value and reduce the service life, but it is still higher than the service life of ordinary filter materials commonly used in the market and is more economical and efficient.

[0075] like Figure 7 As shown, equations (2) and (22) are used together to evaluate the mass loss trend of the sampled samples within 500 days. Regarding the actual wear and breakage curve, in the early operation stage of the filter, the sampled samples were affected by various environmental factors, which resulted in a large mass loss value for some samples, deviating from the overall discrete distribution. In the middle and late stages of operation, the sampled samples have gradually adapted to the water quality and operating conditions in the filter, so the deviation trend has gradually decreased. The quality change trend and law predicted by the actual wear and breakage curve can more accurately provide reference and basis for practical applications, and the fitting straight line R 2 >0.7, further enhancing the scientificity.

[0076] Example 3: Determination of the service life of quartz sand filter material This embodiment adopts a downward flow denitrification biofilter, with quartz sand as the filter material, the inlet COD concentration is 50.1 mg / L, pH <7, the outlet total nitrogen <10 mg / L, the air flushing time is 5 min, the intensity is ≤27.78 L / (m 2 ·s), water flushing time is 10 min, intensity is ≤4.17 L / (m 2 ·s), air-water combined flushing time is 8 min, intensity ≤15.5 L / (m 2 ·s), and the outlet water filtration rate is 6 m / h.

[0077] Assume that the maximum particle size specific surface area of ​​the quartz sand filter material sphere with a particle size range of 1.7 to 3.3 mm is The maximum particle size is ; The specific surface area of ​​the sample sphere is , the diameter is ; The diameter of the marking hole of the sample sphere is , the specific surface area of ​​the spherical caps on both sides of the marked hole is When the specific surface area of ​​the sample after deducting the pore crown ( - ) and the maximum particle size specific surface area of ​​quartz sand filter media When they are equal, according to the above formula (4), the maximum particle size of the common filter media in the filter tank is Particle size of sample The relationship between the diameter of the ball marking hole is shown in Table 2.

[0078] Table 2 Quartz sand filter ball diameter under different multiples According to the data calculated in the above table, select the quartz sand samples for random inspection The particle size was selected as 3.63 mm, based on its physical and chemical properties. The density of quartz sand is usually 2.43g / m 3 , so the initial sample mass is calculated to be 0.61g.

[0079] (twenty four); The quartz sand filter media in the denitrification biofilter was selected as the sampling object. A certain number of filter media particles were sampled at a fixed period (T = 20 days) for 50 consecutive cycles. Based on the sampling data obtained and combined with the above formula (5), the linear function relationship of the quartz sand use cycle change formula (3) was established to obtain the quartz sand wear and breakage curve ( Figure 8 ), the curve fitting degree R 2 =0.7358.

[0080] (3); The actual quartz sand wear and breakage curve is used to predict the quality change of the sample (i.e., the curve change trend is extended until the mass loss reaches 0), and equation (25) is established to obtain the quartz sand wear and breakage prediction curve ( Fig. 9 ), the curve fitting degree R 2 =0.9125.

[0081] (25); After extending the actual quartz sand wear and breakage curve, the goodness of fit of the equation is improved, indicating that the prediction equation is more reliable in estimating the service life of quartz sand. This prediction method can not only reasonably predict the service life of pyrite filter media, but also is applicable to common filter media on the market, which strongly demonstrates the universality of this prediction method.

[0082] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for identifying and screening chaotic samples based on the determination of filter material use cycle, characterized in that: The steps include: (1) Processing of samples to be inspected: Get the maximum particle size of the filter material to be tested ; Make the particle size of the sample to be processed The maximum particle size of the filter material to be tested 1.0~1.1 times of the weight of the sample to be processed; drilling the sample to be processed to obtain a drilled sample, the drilled sample and the filter material to be tested have the same reaction specific surface area; inserting a magnetic metal segment into the pores of the drilled sample, and sealing and covering the two ends of the pores of the drilled sample with colored resin to obtain a marked sample; taking the lowest weight of a single marked sample as the reference weight, making the weight of all the marked samples equal to the reference weight, and obtaining the sample to be tested; (2) Random inspection of samples: The samples to be inspected are put into the filter tank, so that the samples to be inspected and the filter material to be inspected are operated in the same environment; according to the sampling period, through strong magnetic attraction, and / or colored resin, and / or particle size, when the air-water backwashing intensity peaks and the filter layer particles are in an expanded and suspended state, the samples to be inspected are randomly inspected to obtain the samples.

2. The method for identifying and screening chaotic samples based on the determination of filter material use cycle according to claim 1, characterized in that: The processing of the sample to be sampled in step (1) includes the following specific steps: (1-1) Collect the particle size range of the filter material to be tested and obtain the maximum particle size of the filter material to be tested ; Make the particle size of the sample to be processed The maximum particle size of the filter material to be tested 1.0~1.1 times of the particle size of the sample to be processed , obtaining the drilling diameter of the sample to be processed; (1-2) drilling the sample to be processed according to the drilling diameter of the sample to be processed to obtain a drilled sample, wherein the drilled sample has the same reaction specific surface area as the filter material to be tested; inserting a magnetic metal segment into the pores of the drilled sample, and sealing and covering both ends of the pores of the drilled sample with a colored resin to obtain a marked sample; (1-3) The marked samples are uniformly weighed, and the lowest weight of a single marked sample is used as the reference weight. The marked samples that exceed the reference weight are ground so that the weight of all the marked samples is equal to the reference weight, thereby obtaining the samples to be inspected.

3. The method for identifying and screening chaotic samples based on the determination of filter material use cycle according to claim 2, characterized in that: The specific method of obtaining the drilling diameter of the sample to be processed in step (1-1) is as follows: the drilling diameter of the sample to be processed is calculated by the following formula (1); formula (1) is as follows: （1）； In formula (1) is the particle size of the sample to be processed, N is the diameter of the drill hole of the sample to be processed, and the value range of N is 1.0~1.

1.

4. The method for identifying and screening chaotic samples based on the determination of filter material use cycle according to claim 2, characterized in that: The magnetic metal segment in step (1-2) comprises an alloy of one or at least two of iron, nickel and cobalt; the diameter of the magnetic metal segment is not greater than the borehole diameter of the sample to be processed, and the length of the magnetic metal segment is less than the borehole length of the sample to be processed; The colored resin in step (1-2) includes at least one of colored epoxy resin, alkyd resin, phenolic resin and polyurethane resin.

5. The method for identifying and screening chaotic samples based on the determination of filter material use cycle according to claim 1, characterized in that: The random inspection of the samples in step (2) includes the following specific steps: (2-1) placing the sample to be inspected into a specific range of the filter layer of the filter tank, so that the sample to be inspected and the filter material to be inspected are operated in the same environment; (2-2) According to the sampling period, the sample to be inspected is randomly selected within the specific range by strong magnetic attraction, and / or colored resin, and / or particle size, when the filter layer particles are in an expanded and suspended state at the peak of the air-water backwash intensity, to obtain the sample to be inspected.

6. The method for identifying and screening chaotic samples based on the determination of filter material use cycle according to claim 5, characterized in that: In step (2-1), the specific range of the filter layer of the filter tank is obtained by a perforated enclosure; the side length of the perforated enclosure is 1.2m~2m, and the height of the perforated enclosure exceeds the filter tank flooding by more than 20 cm.

7. The method for identifying and screening chaotic samples based on the determination of filter material use cycle according to claim 5, characterized in that: In step (2-2), the sampling period interval is at least 10 days, and the continuous sampling is at least 50 periods.

8. Application of the sample sampled by the method for identifying and screening chaotic samples based on the determination of the filter material use period as described in any one of claims 1 to 7 in the construction of a model for the determination of the use period of the filter material to be tested.

9. A method for constructing a model for determining the service life of a filter material, characterized in that: The method comprises the following steps: recording the quality data of each sampling period of the random inspection sample of the chaotic sample identification and screening method based on the determination of the filter material use period as described in any one of claims 1 to 7, and fitting the mass loss curve; and determining the use period of the filter material to be inspected according to the fitted mass loss curve.

10. The method for constructing a model for measuring the service life of a filter material according to claim 9, characterized in that: When the filter material to be tested is pyrite filter material, the equation of the mass loss curve is shown in formula (2): （2）； In formula (2), x is the service life of pyrite filter material; y is the mass of pyrite filter material corresponding to a certain period; When the filter material to be tested is quartz sand filter material, the equation of the mass loss curve is shown in formula (3): （3）； In formula (3), x is the service life of quartz sand filter material; y is the mass of quartz sand filter material corresponding to a certain period.

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