Device and method for evaluating filler of sewage treatment percolation system

Abstract

The invention relates to a filler evaluation device and method for a sewage treatment percolation system, and belongs to the technical field of sewage treatment.The device comprises a shell, a water distribution-fine filtration mixing layer, a percolation system filler layer and a ceramsite supporting layer, and the water distribution-fine filtration mixing layer, the percolation system filler layer and the ceramsite supporting layer are sequentially arranged in the shell at intervals in the sewage flowing direction; wherein the filler layer of the percolation system is filled with filler to be evaluated. The evaluation device is simple in structure and small in occupied area, a plurality of devices can be arranged to measure and verify functional indexes of various fillers at the same time, the data acquisition efficiency is improved, meanwhile, the operation process is simple and convenient, complex auxiliary equipment is not needed, and operation is easy. According to the evaluation method, the EWM-TOPSIS method is adopted, the index weight is determined according to the variation degree of each index value, deviation caused by human factors is avoided, the weight precision is high, the objectivity is high, each index weight distribution is scientific, original data information is fully utilized, and the filler evaluation result better conforms to the actual situation.

Description

Technical Field

[0001] The invention relates to the technical field of sewage treatment, and in particular to a device and method for evaluating filler in a sewage treatment infiltration system. Background Art

[0002] As a low-cost and easy-to-manage sewage treatment process, the land infiltration system is widely used in rural sewage treatment scenarios. The land infiltration system has a complex biological, physical, and chemical combined action process, which can adsorb, degrade, and transform various compounds. The filler plays a core role in the sewage treatment effect of the system. Traditional fillers are mainly natural minerals such as gravel, zeolite, and limestone, and industrial and agricultural by-products such as coke, broken pottery, and straw. These fillers are heavy and difficult to transport, resulting in high system construction costs. Therefore, it is necessary to consider using lightweight fillers to replace traditional fillers. The lightweight process of the land infiltration system requires an accurate evaluation of the application effect of the lightweight filler to determine whether the lightweight filler can replace the traditional infiltration system filler. Therefore, it is necessary to provide an objective and effective evaluation plan for the selection of lightweight fillers.

[0003] The comprehensive evaluation of materials generally includes the construction of the evaluation index system structure and the determination of the index weights. The construction of the system structure is the basic work, which is used to determine and process the evaluation index. The main construction methods are the target decomposition method and the survey method. In addition, the determination of the index weights is a key task, which mainly includes two types: subjective weighting method and objective weighting method. Subjective weighting methods include Delphi method, hierarchical analysis method, and expert consultation method. Objective weighting methods include principal component analysis method, entropy method, and factor analysis method. The above evaluation methods have shortcomings such as being too subjective or having inherent limitations in a single decision-making method. On the other hand, the current research on land infiltration systems in the field of sewage treatment technology mainly involves aspects such as device structure, enhanced biochemical reaction, and filler filling scheme. However, there is still a lack of filler decision-making methods in the lightweight process of land infiltration systems, and it is impossible to provide accurate evaluation standards and schemes for actual engineering applications.

[0004] Therefore, in view of the above technical background issues, it is urgent to establish a method for evaluating fillers in sewage treatment infiltration systems, scientifically and efficiently evaluate the application effects of fillers, and provide theoretical support for the selection of fillers in sewage treatment infiltration systems. Summary of the invention

[0005] In order to scientifically and efficiently evaluate the application effect of fillers and provide theoretical support for the selection of fillers in sewage treatment infiltration systems, the present invention provides a sewage treatment infiltration system filler evaluation device and method. This method establishes an evaluation model for infiltration system fillers, and evaluates the application effect of fillers from three aspects: filler strength index, filler adsorption performance index, and effluent water quality index. The effluent water quality index is obtained by constructing a sewage treatment infiltration system filler evaluation device, using cylinder pressure strength, wear rate, specific surface area, pollutant adsorption amount, chemical oxygen demand, ammonia nitrogen concentration, total nitrogen concentration, and total phosphorus concentration as evaluation indicators, using the EWM method to determine the weight of each evaluation index, and then using the TOPSIS method to assign points and sort each method, and select the best performance filler.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] One of the purposes of the present invention is to provide a filler evaluation device for a sewage treatment infiltration system, comprising a housing, and also comprising a water distribution-fine filtration mixing layer, an infiltration system filler layer and a ceramsite support layer which are sequentially arranged in the housing according to the flow direction of the sewage;

[0008] Wherein, the filler to be evaluated is filled in the filler layer of the filtration system.

[0009] Furthermore, the shell is also provided with a water inlet and a water outlet, and the water inlet is located above the water outlet. Preferably, the water inlet and the water outlet are respectively arranged on both sides of the water-fine filtration mixing layer, the infiltration system filler layer and the ceramsite supporting layer, and the water inlet is located above the water outlet.

[0010] Furthermore, the distance between the water inlet and the top of the device housing is 30 mm, and the distance between the water outlet and the bottom of the device is 20 mm.

[0011] Furthermore, the water inlet is connected to the water inlet bucket through a pipe, and the water outlet is connected to the water storage bottle through a pipe.

[0012] Furthermore, the water distribution-fine filtration mixed layer is filled and constructed by fine river sand, ordinary ceramsite and gravel, and meets the following requirements:

[0013] In the present invention, the particle size of the fine river sand is 80-100 mesh;

[0014] In the present invention, the particle size of the common ceramsite is 10-15 mm;

[0015] In the present invention, the particle size of the gravel is 3-5 mm;

[0016] In the present invention, the filling ratio of the fine river sand, the common ceramsite and the gravel is 2:1:1.

[0017] Furthermore, the ceramsite supporting layer is constructed by filling gravel and common ceramsite and meets the following requirements:

[0018] In the present invention, the particle size of the gravel is 3-5 mm;

[0019] In the present invention, the particle size of the common ceramsite is 10-15 mm;

[0020] In the present invention, the filling ratio of the gravel to the common ceramsite is 1:2.

[0021] Furthermore, the evaluation device also satisfies:

[0022] In the present invention, the size of the housing is 200mm×200mm×400mm;

[0023] In the present invention, the thickness of the water distribution-fine filtration mixed layer is 60 mm;

[0024] In the present invention, the thickness of the filler layer of the filtration system is 240 mm;

[0025] In the present invention, the thickness of the ceramsite supporting layer is 40 mm.

[0026] The second object of the present invention is to provide a method for evaluating filler in a sewage treatment infiltration system, the method comprising:

[0027] Step 1: Establish an evaluation index system, including primary, secondary and tertiary indicators.

[0028] The first-level index includes filler property index and filler function index;

[0029] The secondary indicators under the filler property index in the first-level index are the filler strength index and the filler adsorption performance index, and the secondary indicator under the filler function index in the first-level index is the effluent water quality index;

[0030] The third-level indicators under the filler strength indicator in the second-level indicator are cylinder pressure strength f a and wear rate C b The third-level indicators under the filler adsorption performance index in the secondary index are specific surface area S w and the amount of pollutant adsorbed q e The third-level indicators under the effluent water quality indicators in the second-level indicators are chemical oxygen demand C COD , ammonia nitrogen concentration C NH3-N , total nitrogen concentration C TN and total phosphorus concentration C TP ;

[0031] Step 2: Obtain specific data of each evaluation index to form a packing cylinder pressure strength f a , wear rate Cb , specific surface area S w , pollutant adsorption amount q e , chemical oxygen demand C COD , ammonia nitrogen concentration C NH3-N , total nitrogen concentration C TN , total phosphorus concentration C TP The original filler performance data matrix for the main evaluation indicators;

[0032] The sewage is connected to the water inlet 4 of the sewage treatment infiltration system filler evaluation device as described above, and the sewage flows through the water distribution-fine filtration mixed layer 1, the infiltration system filler layer 2 and the ceramsite support layer 3 in sequence. The effluent from the water outlet 5 is collected on a daily basis to measure the chemical oxygen demand C. COD , ammonia nitrogen concentration C NH3-N , total nitrogen concentration C TN , total phosphorus concentration C TP ;

[0033] Step 3: Calculate the weight of each evaluation index based on the EWM-TOPSIS method, obtain the comprehensive evaluation scores of different fillers and rank them, and obtain the evaluation results of different filtration system fillers.

[0034] Further, in step 2, the original filler performance data matrix is ​​defined as:

[0035] X=(X1,X2,...,X m )=(x ij ) ×m (i=1, 2,..., n, j=1, 2,..., m);

[0036] Where X is the original filler performance data matrix of n fillers evaluated by m indicators.

[0037] Furthermore, in step 3, the process of calculating the weights of each evaluation index based on the EWM method is as follows:

[0038] The evaluation indicators were standardized with the same trend by using the range analysis method. The cylinder pressure strength, specific surface area and pollutant adsorption were used as positive indicators for positive standardization. The wear rate, chemical oxygen demand, ammonia nitrogen concentration, total nitrogen concentration and total phosphorus concentration were used as negative indicators for reverse standardization.

[0039]

[0040] In the formula, x′ ij is the jth evaluation index data of the i-th filler after positive normalization;

[0041] Get the forward normalization matrix:

[0042] X′=(X′1,X′2,...,X′ m )=(x′ ij ) n×m (i=1,2,...,n,j=1,2,...,m);

[0043] Perform a non-negative translation operation on the positive normalized matrix X′ to obtain a normalized matrix suitable for subsequent calculations:

[0044] Y=(Y1,Y2,...,Y m )=(y ij ) n×m (i=1, 2,..., n, j=1, 2,..., m);

[0045] Create a weight matrix:

[0046] P=(p ij ) n×m ,in,

[0047] Where p ij is the proportion of index j of the i-th filler in the index;

[0048] Calculate the information entropy of the jth indicator:

[0049]

[0050] Finally, the weights of each indicator are obtained:

[0051]

[0052] Furthermore, in step 3, the process of calculating the comprehensive evaluation score of the filler using the TOPSIS method is as follows:

[0053] The index weights determined by the EWM method are used to weight the standardized matrix:

[0054] Weighted normalization matrix Z = (Z1, Z2, ..., Z m )=(z ij ) n×m where z ij =w j ×y ij , (i=1,2,...,n,j=1,2,...,m);

[0055] According to the weighted normalization matrix, the positive ideal solution and the negative ideal solution are determined.

[0056] The positive ideal solution is:

[0057] The negative ideal solution is:

[0058] Then calculate the Euclidean distance between each filler to be evaluated and the positive ideal solution and the negative ideal solution.

[0059] The positive ideal solution distance is:

[0060] The negative ideal solution distance is:

[0061] Finally, calculate the comprehensive evaluation score of each filler to be evaluated

[0062] The comprehensive evaluation scores are ranked to obtain the evaluation results of the fillers of the sewage treatment infiltration system, so as to select the fillers with the best performance.

[0063] Furthermore, in step 2, the sewage introduced through the water inlet is fed with a hydraulic load not exceeding 0.03 m / h, and the water flowing out of the water outlet is stored in a water storage bottle on a daily basis.

[0064] Compared with the prior art, the present invention has the following advantages:

[0065] (1) The evaluation device provided by the present invention has a simple structure and occupies a small area. Multiple devices can be set up to measure and verify the functional indicators of multiple fillers at the same time, thereby improving data acquisition efficiency. At the same time, the operation process is simple and convenient, does not require complex auxiliary equipment, and is easy to operate.

[0066] (2) The evaluation method provided by the present invention adopts the EWM-TOPSIS method to determine the index weight according to the degree of variation of the numerical values ​​of each index, thereby avoiding the deviation caused by human factors, making the weight more accurate and more objective, and the weight allocation of each index more scientific. At the same time, the original data information is fully utilized, and the results of filler evaluation are more in line with the actual situation.

[0067] (3) The evaluation method provided by the present invention introduces the EWM-TOPSIS method into the evaluation process of the filler of the sewage treatment infiltration system, which can realize the accurate evaluation of the filler of the sewage treatment infiltration system. BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Figure 1 It is a schematic diagram of the structure of the device of the present invention;

[0069] Figure 2 It is a schematic diagram of the process of the present invention;

[0070] The numbers in the figure are as follows: 1-water distribution-fine filtration mixing layer; 2-filtration system filler layer; 3-ceramsite supporting layer; 4-water inlet; 5-water outlet. DETAILED DESCRIPTION

[0071] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0072] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0073] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "coupled" should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0074] The present invention provides a method for evaluating filler in a sewage treatment infiltration system, the method comprising:

[0075] Step 1: Establish an evaluation index system, including primary, secondary and tertiary indicators.

[0076] The first-level index includes filler property index and filler function index;

[0077] The secondary indicators under the filler property index in the first-level index are the filler strength index and the filler adsorption performance index, and the secondary indicator under the filler function index in the first-level index is the effluent water quality index;

[0078] The third-level indicators under the filler strength indicator in the second-level indicator are cylinder pressure strength f a and wear rate C b The third-level indicators under the filler adsorption performance index in the secondary index are specific surface area S w and the amount of pollutant adsorbed q e The third-level indicators under the effluent water quality indicators in the second-level indicators are chemical oxygen demand C COD , ammonia nitrogen concentration C NH3-N , total nitrogen concentration C TN and total phosphorus concentration C TP ;

[0079] Step 2: Obtain specific data of each evaluation index to form a packing cylinder pressure strength f a , wear rate C b , specific surface area S w , pollutant adsorption amount q e , chemical oxygen demand C COD , ammonia nitrogen concentration C NH3-N , total nitrogen concentration C TN , total phosphorus concentration C TP The original filler performance data matrix for the main evaluation indicators;

[0080] Among them, chemical oxygen demand C COD , ammonia nitrogen concentration C NH3-N , total nitrogen concentration C TN , total phosphorus concentration C TP The measurement is carried out with the aid of a sewage treatment infiltration system filler evaluation device provided by the present invention, which comprises a shell, and also comprises a water distribution-fine filtration mixing layer, an infiltration system filler layer and a ceramsite supporting layer which are sequentially arranged in the shell according to the sewage flow direction; wherein the infiltration system filler layer is filled with filler to be evaluated.

[0081] In some embodiments of the present invention, the shell is further provided with a water inlet 4 and a water outlet 5, and the water inlet 4 is located above the water outlet 5. Preferably, the water inlet 4 and the water outlet 5 are respectively arranged on both sides of the water-fine filtration mixing layer 1, the infiltration system filler layer 2 and the ceramsite supporting layer 3, and the water inlet 4 is located above the water outlet 5. The distance between the water inlet 4 and the top of the device shell is 30 mm, and the distance between the water outlet 5 and the bottom of the device is 20 mm. The water inlet 4 is connected to the water inlet bucket through a pipe, and the water outlet 5 is connected to the water storage bottle through a pipe.

[0082] In some embodiments of the present invention, the water distribution-fine filtration mixed layer 1 is filled and constructed by fine river sand, ordinary expanded clay and gravel, and meets the following requirements: the particle size of the fine river sand is 80-100 mesh; the particle size of the ordinary expanded clay is 10-15mm; the particle size of the gravel is 3-5mm; the filling ratio of the fine river sand, the ordinary expanded clay and the gravel is 2:1:1.

[0083] In some embodiments of the present invention, the expanded clay supporting layer 3 is constructed by filling gravel and ordinary expanded clay, and satisfies: the particle size of the gravel is 3-5mm; the particle size of the ordinary expanded clay is 10-15mm; the filling ratio of the gravel to the ordinary expanded clay is 1:2.

[0084] In some embodiments of the present invention, the evaluation device also meets the following requirements: the size of the shell is 200mm×200mm×400mm; the thickness of the water distribution-fine filtration mixing layer 1 is 60mm; the thickness of the infiltration system filler layer 2 is 240mm; and the thickness of the expanded clay supporting layer 3 is 40mm.

[0085] Specifically, sewage is connected through the water inlet 4 of the sewage treatment infiltration system filler evaluation device as described above, and water is fed in at a hydraulic load not exceeding 0.03 m / h. The water outlet 5 is connected to a water storage bottle, and the sewage flows through the water distribution-fine filtration mixed layer 1, the infiltration system filler layer 2 and the ceramsite support layer 3 in sequence. The water flowing out of the water outlet 5 is collected on a daily basis, and the chemical oxygen demand C is measured. COD , ammonia nitrogen concentration C NH3-N , total nitrogen concentration C TN , total phosphorus concentration C TP ;

[0086] Step 3: Calculate the weight of each evaluation index based on the EWM-TOPSIS method, obtain the comprehensive evaluation scores of different fillers and rank them, and obtain the evaluation results of different filtration system fillers.

[0087] Further, in step 2, the original filler performance data matrix is ​​defined as:

[0088] X=(X1,X2,...,X m )=(x ij ) n×m (i=1, 2,..., n, j=1, 2,..., m);

[0089] Where X is the original filler performance data matrix of n fillers evaluated by m indicators.

[0090] In some embodiments of the present invention, in step 3, the process of calculating the weight of each evaluation index based on the EWM method is as follows:

[0091] The evaluation indicators were standardized with the same trend by using the range analysis method. The cylinder pressure strength, specific surface area and pollutant adsorption were used as positive indicators for positive standardization. The wear rate, chemical oxygen demand, ammonia nitrogen concentration, total nitrogen concentration and total phosphorus concentration were used as negative indicators for reverse standardization.

[0092]

[0093] In the formula, x′ ij is the jth evaluation index data of the i-th filler after positive normalization;

[0094] Get the forward normalization matrix:

[0095] X′=(X′1,X′2,...,X′m )=(x′ ij ) n×m (i=1,2,...,n,j=1,2,...,m);

[0096] Perform a non-negative translation operation on the positive normalized matrix X′ to obtain a normalized matrix suitable for subsequent calculations:

[0097] Y=(Y1,Y2,...,Y m )=(y ij ) n×m (i=1,2,...,n,j=1,2,...,m);

[0098] Create a weight matrix:

[0099] P=(p ij ) n×m in,

[0100] Where p ij is the proportion of index j of the i-th filler in the index;

[0101] Calculate the information entropy of the jth indicator:

[0102]

[0103] Finally, the weights of each indicator are obtained:

[0104]

[0105] In some embodiments of the present invention, in step 3, the process of calculating the comprehensive evaluation score of the filler using the TOPSIS method is as follows:

[0106] The index weights determined by the EWM method are used to weight the standardized matrix:

[0107] Weighted normalization matrix Z = (Z1, Z2, ..., Z m )=(z ij ) n×m where z ij =w j ×y ij , (i=1,2,...,n,j=1,2,...,m);

[0108] According to the weighted normalization matrix, the positive ideal solution and the negative ideal solution are determined.

[0109] The positive ideal solution is:

[0110] The negative ideal solution is:

[0111] Then calculate the Euclidean distance between each filler to be evaluated and the positive ideal solution and the negative ideal solution.

[0112] The positive ideal solution distance is:

[0113] The negative ideal solution distance is:

[0114] Finally, calculate the comprehensive evaluation score of each filler to be evaluated

[0115] The comprehensive evaluation scores are ranked to obtain the evaluation results of the fillers of the sewage treatment infiltration system, so as to select the fillers with the best performance.

[0116] Example

[0117] The existing filler decision-making methods in the lightweight process of land infiltration systems are still lacking and cannot provide accurate evaluation standards and solutions for actual engineering applications.

[0118] In order to scientifically and efficiently evaluate the application effect of fillers and provide theoretical support for the selection of fillers in sewage treatment and infiltration systems, the present invention provides a method for evaluating fillers in sewage treatment and infiltration systems. The specific process is shown in Figure 2 , including the following steps:

[0119] Step 1: Establish an evaluation index system, see Table 1, which includes primary, secondary and tertiary indicators.

[0120] The first-level index includes filler property index and filler function index;

[0121] The secondary indicators under the filler property index in the first-level index are the filler strength index and the filler adsorption performance index, and the secondary indicator under the filler function index in the first-level index is the effluent water quality index;

[0122] The third-level indicators under the filler strength indicator in the second-level indicator are cylinder pressure strength f a and wear rate C b The third-level indicators under the filler adsorption performance index in the secondary index are specific surface area S w and the amount of pollutant adsorbed q e The third-level indicators under the effluent water quality indicators in the second-level indicators are chemical oxygen demand C COD , ammonia nitrogen concentration C NH3-N , total nitrogen concentration C TN and total phosphorus concentration C TP .

[0123] Of course, this embodiment can also determine an open index system based on specific filler characteristics, and its concept should also be included in the protection scope of this application. This embodiment does not go into detail, and only uses the above-mentioned primary index, secondary index and tertiary index as examples for explanation.

[0124] Table 1 Evaluation index system

[0125]

[0126]

[0127] Step 2: Obtain specific data of each evaluation index to form a packing cylinder pressure strength f a , wear rate C b , specific surface area S w , pollutant adsorption amount q e , chemical oxygen demand C COD , ammonia nitrogen concentration C NH3-N , total nitrogen concentration C TN , total phosphorus concentration C TP The original filler performance data matrix for the main evaluation indicators;

[0128] (1) Cylinder pressure strength f a The acquisition process is: according to the "Light Aggregate Test Method" (GB / T17431.2-2010), the relevant factors are measured, and the cylinder pressure strength calculation formula of the filler is:

[0129]

[0130] In the formula, f a is the cylinder pressure strength of the filler, in MPa; p1 is the pressure value when the pressing depth is 20mm, in N; p2 is the mass of the stamping die, in N; F is the pressure-bearing area (i.e. the stamping die area F = 10000mm 2 ).

[0131] (2) Wear rate C b The acquisition process is as follows: using the rotating collision method, a certain mass of filler is weighed, and it is placed in a container together with the rolling beads. It is run in a constant temperature oscillator at 20°C and 200r / min for 24h, and the mass of the remaining filler is taken out and weighed. The wear rate of the filler is calculated as follows:

[0132]

[0133] In the formula, C b is the wear rate; m b is the mass of the filler sample after oscillation, in g; m is the total mass of the filler sample, in g.

[0134] (3) Specific surface area Sw The acquisition process is: according to the steps of "Determination of Specific Surface Area of ​​Solid Substances by Gas Adsorption BET Method" (GB / T19587-2017), the relevant factors are measured, and the specific surface area calculation process of the filler is:

[0135]

[0136] Where P is the equilibrium adsorption pressure, in Pa; P0 is the saturated vapor pressure, in Pa; V is the adsorption volume, in cm 3 ; V m is the monolayer adsorption volume in cm 3 ; C is the BET constant;

[0137] Let P / P0 be X, For Y, For A, =B, and a straight line equation Y = AX + B is obtained. Through a series of measurements of relative pressure P / P0 and adsorbed gas volume V, the slope A and intercept B are calculated from the BET diagram, thereby obtaining the monolayer capacity and BET constant C;

[0138] The specific surface area of ​​the filler can be calculated by the monolayer capacity and the average area occupied by each molecule in a complete monolayer. The formula is:

[0139]

[0140] In the formula, S w is the mass specific surface area of ​​the sample, in units of 10 4 cm 2 / g; m is the mass of the sample, in g.

[0141] (4) In this embodiment, the pollutant imidacloprid is taken as an example, and the pollutant adsorption amount q e The acquisition process is as follows: weigh a portion of the filler sample and put it into a 50 mg / L imidacloprid solution, put it into a constant temperature oscillator, oscillate it for 24 hours at a temperature of 25°C and a speed of 200 r / min, take samples to measure the imidacloprid concentration in the solution before and after adsorption, and the calculation formula for the imidacloprid adsorption of the filler is:

[0142]

[0143] In the formula, q e is the imidacloprid adsorption amount of the sample, in mg / g; V is the volume of the imidacloprid solution, in L; C0 is the imidacloprid concentration of the solution before adsorption, in mg / L; C is the imidacloprid concentration of the solution after adsorption, in mg / L; m is the mass of the added sample, in g.

[0144] (5) The process of obtaining effluent water quality indicators is as follows: Figure 1 The device shown is filled with the filler to be evaluated, and the simulated sewage is used to run continuously for 25 days. Water samples are taken every day to measure the concentrations of four water quality indicators, and finally the average concentration of each water quality indicator is calculated as the indicator data; the specific steps are as follows: the sewage is connected through the water inlet 4 of the sewage treatment infiltration system filler evaluation device as described above, and the sewage flows through the water distribution-fine filtration mixed layer 1, the infiltration system filler layer 2 and the ceramsite support layer 3 in sequence, and the effluent from the water outlet 5 is collected on a daily basis to measure the chemical oxygen demand C COD , ammonia nitrogen concentration C NH3-N , total nitrogen concentration C TN , total phosphorus concentration C TP ;

[0145] The concentration of water quality indicators is determined and calculated according to four national standards: "Water Quality - Determination of Chemical Oxygen Demand - Rapid Digestion Spectrophotometric Method" (HJ / T399-2007), "Water Quality - Determination of Ammonia Nitrogen - Nessler's Reagent Spectrophotometric Method" (HJ535-2009), "Water Quality - Determination of Total Nitrogen - Alkaline Potassium Persulfate Digestion Ultraviolet Spectrophotometric Method" (HJ636-2012), and "Water Quality - Determination of Total Phosphorus - Ammonium Molybdate Spectrophotometric Method" (GB11893-89).

[0146] Table 2 shows the specific data of the evaluation indicators.

[0147] Filling ID <![CDATA[f a ]]> <![CDATA[C b ]]> <![CDATA[S w ]]> <![CDATA[q e ]]> <![CDATA[C COD ]]> <![CDATA[C NH3-N ]]> <![CDATA[C TN ]]> <![CDATA[C TP ]]> 1 6.5 2.1％ 1.5 13.9 50.3 1.6 24.0 2.2 2 5.1 5.0％ 8.3 35.1 42.3 1.3 21.6 1.9 3 5.5 5.9％ 10.8 40.6 66.3 0.8 25.5 2.0 4 7.3 3.1％ 0.7 11.3 49.5 2.1 22.7 2.6

[0148] Finally, the original filler performance data matrix composed of the evaluation indicators of several fillers to be evaluated is defined as:

[0149] X=(X1,X2,...,X m )=(x ij ) n×m (i=1, 2,..., n, j=1, 2,..., m);

[0150] Where X is the original filler performance data matrix of n fillers evaluated by m indicators.

[0151] Step 3: Calculate the weight of each evaluation index based on the EWM method;

[0152] The evaluation indicators were standardized with the same trend by using the range analysis method. The data in Table 2 were processed by taking the cylinder pressure strength, specific surface area and pollutant adsorption as positive indicators for positive standardization, and taking the wear rate, chemical oxygen demand, ammonia nitrogen concentration, total nitrogen concentration and total phosphorus concentration as negative indicators for reverse standardization:

[0153]

[0154] In the formula, x′ ijis the jth evaluation index data of the i-th filler after positive normalization;

[0155] Finally, the forward normalized matrix is ​​obtained:

[0156] X′=(X′1,X′2,...,X′ m )=(x′ ij ) n×m (i=1, 2,..., n, j=1, 2,..., m);

[0157] The forward normalization matrix obtained according to the above method is:

[0158]

[0159] Perform a non-negative translation operation on the positive normalized matrix X′ to obtain a normalized matrix suitable for subsequent calculations:

[0160] Y=(Y1,Y2...,Y m )=(y ij ) n×m (i=1, 2,..., n, j=1, 2,..., m);

[0161] The non-negative translation normalization matrix obtained according to the above method is:

[0162]

[0163] Then create the weight matrix:

[0164] P=(p ij ) n×m ,in,

[0165] Where p ij is the proportion of index j of the i-th filler in the index;

[0166] The weight matrix obtained according to the above method is:

[0167]

[0168] Calculate the information entropy of the jth indicator:

[0169]

[0170] Calculate the weight of each evaluation index:

[0171]

[0172] Table 3 shows the weights of each evaluation index obtained according to the above method:

[0173] Evaluation indicators <![CDATA[f a ]]> <![CDATA[C b ]]> <![CDATA[S w ]]> <![CDATA[q e ]]> <![CDATA[C COD ]]> <![CDATA[C NH3-N ]]> <![CDATA[C TN ]]> <![CDATA[C TP ]]> <![CDATA[Weight w j > 0.1389 0.1268 0.1677 0.1639 0.0922 0.1087 0.1073 0.0945

[0174] The weighted standardization matrix is ​​calculated according to the weights of each evaluation index recorded in Table 3

[0175] Z=( Z1， Z2, ..., Z m )=(z ij ) n×m ,

[0176] where z ij =w j ×y ij , (i=1,2,...,n,j=1,2,...,m):

[0177]

[0178] Step 4: Calculate the comprehensive evaluation scores of the fillers based on the TOPSIS method and rank them to obtain the evaluation results of fillers in different infiltration systems;

[0179] First, the positive ideal solution and negative ideal solution are determined according to the weighted normalization matrix:

[0180] Positive ideal solution

[0181] Negative ideal solution

[0182] Then calculate the Euclidean distance between each filler to be evaluated and the positive ideal solution and the negative ideal solution:

[0183] Positive ideal solution distance

[0184] Negative ideal solution distance

[0185] Table 4 shows the positive ideal solution and negative ideal solution distances of several fillers obtained according to the above method:

[0186]

[0187] Finally, the comprehensive evaluation score of each filler to be evaluated is calculated according to Table 4:

[0188]

[0189] The comprehensive evaluation scores are ranked to obtain the evaluation results of the fillers of the sewage treatment infiltration system, so as to select the fillers with the best performance.

[0190] Table 5 shows the comprehensive evaluation scores and rankings of several fillers obtained according to the above steps:

[0191]

[0192]

[0193] According to Table 4, it can be concluded that filler No. 3 performs best in the sewage treatment infiltration system.

[0194] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. A filler evaluation device for a sewage treatment infiltration system, comprising a housing, characterized in that: It also includes a water distribution-fine filtration mixing layer (1), a percolation system filler layer (2) and a ceramsite supporting layer (3) which are sequentially arranged in intervals in the shell according to the flow direction of the sewage; Wherein, the filler to be evaluated is filled in the filler layer (2) of the filtration system.

2. A sewage treatment infiltration system filler evaluation device according to claim 1, characterized in that: The shell is also provided with a water inlet (4) and a water outlet (5), and the water inlet (4) is located above the water outlet (5).

3. A sewage treatment infiltration system filler evaluation device according to claim 1, characterized in that: The water distribution-fine filtration mixed layer (1) is filled and constructed with fine river sand, ordinary ceramsite and gravel, and meets at least one of the following conditions: ① The particle size of the fine river sand is 80-100 mesh; ② The particle size of the ordinary ceramsite is 10-15mm; ③ The particle size of the gravel is 3-5 mm; ④ The filling ratio of the fine river sand, the ordinary expanded clay and the gravel is 2:1:

1.

4. A sewage treatment infiltration system filler evaluation device according to claim 1, characterized in that: The ceramsite supporting layer (3) is constructed by filling gravel and common ceramsite and meets at least one of the following conditions: ① The particle size of the gravel is 3-5 mm; ② The particle size of the ordinary ceramsite is 10-15mm; ③ The filling ratio of the gravel to the common expanded clay is 1:

2.

5. A sewage treatment infiltration system filler evaluation device according to claim 1, characterized in that: The evaluation device satisfies at least one of the following conditions: ① The size of the housing is 200mm×200mm×400mm; ② The thickness of the water distribution-fine filtration mixed layer (1) is 60 mm; ③ The thickness of the filler layer (2) of the filtration system is 240 mm; ④ The thickness of the ceramsite supporting layer (3) is 40 mm.

6. A method for evaluating fillers in a sewage treatment infiltration system, characterized in that: The evaluation method includes: Step 1: Establish an evaluation index system, including primary, secondary and tertiary indicators. The first-level index includes filler property index and filler function index; The secondary indicators under the filler property index in the first-level index are the filler strength index and the filler adsorption performance index, and the secondary indicator under the filler function index in the first-level index is the effluent water quality index; The third-level indicators under the filler strength index in the secondary index are cylinder pressure strength and wear rate, the third-level indicators under the filler adsorption performance index in the secondary index are specific surface area and pollutant adsorption capacity, and the third-level indicators under the effluent water quality index in the secondary index are chemical oxygen demand, ammonia nitrogen concentration, total nitrogen concentration and total phosphorus concentration; Step 2: Obtain specific data for each evaluation index to form an original filler performance data matrix with filler cylinder pressure strength, wear rate, specific surface area, pollutant adsorption, chemical oxygen demand, ammonia nitrogen concentration, total nitrogen concentration, and total phosphorus concentration as main evaluation indicators; Wherein, sewage is connected through the water inlet (4) of the sewage treatment infiltration system filler evaluation device as described in any one of claims 1 to 5, and the sewage flows through the water distribution-fine filtration mixed layer (1), the infiltration system filler layer (2) and the ceramsite support layer (3) in sequence, and the effluent flowing out of the water outlet (5) is collected on a daily basis to measure the chemical oxygen demand, ammonia nitrogen concentration, total nitrogen concentration and total phosphorus concentration; Step 3: Calculate the weight of each evaluation index based on the EWM-TOPSIS method, obtain the comprehensive evaluation scores of different fillers and rank them, and obtain the evaluation results of different filtration system fillers.

7. A method for evaluating fillers in a sewage treatment infiltration system according to claim 6, characterized in that: In step 2, the original filler performance data matrix is ​​defined as: X=(X1,X2,...,X m )=(x ij ) n×m (i=1,2,...,n, j=1,2,...,m)? Where X is the original filler performance data matrix of n fillers evaluated by m indicators.

8. A method for evaluating fillers in a sewage treatment infiltration system according to claim 6, characterized in that: In step 3, the process of calculating the weights of each evaluation index based on the EWM method is as follows: The evaluation indicators were standardized with the same trend by using the range analysis method. The cylinder pressure strength, specific surface area and pollutant adsorption were used as positive indicators for positive standardization. The wear rate, chemical oxygen demand, ammonia nitrogen concentration, total nitrogen concentration and total phosphorus concentration were used as negative indicators for reverse standardization. In the formula, x′ ij is the jth evaluation index data of the i-th filler after positive normalization; Get the forward normalization matrix: X′=(X′1,X′2,...,X′ m )=(x′ ij ) n×m (i=1,2,...,n,j=1,2,...,m); Perform a non-negative translation operation on the positive normalized matrix X′ to obtain a normalized matrix suitable for subsequent calculations: Y=(Y1,Y2,...,Y m )=(y ij ) n×m (i=1,2,...,n,j=1,2,...,m); Create a weight matrix: P=(p ij ) n×m ,in, Where p ij is the proportion of index j of the i-th filler in the index; Calculate the information entropy of the jth indicator: Finally, the weights of each indicator are obtained:

9. A method for evaluating fillers in a sewage treatment infiltration system according to claim 6, characterized in that: In step 3, the process of calculating the comprehensive evaluation score of the filler using the TOPSIS method is as follows: The index weights determined by the EWM method are used to weight the standardized matrix: Weighted normalization matrix: Z = (Z1, Z2, ..., Z m )=(z ij ) n×m , where z ij =w j ×y ij , (i=1,2,...,n,j=1,2,...,m); According to the weighted normalization matrix, the positive ideal solution and the negative ideal solution are determined. The positive ideal solution is: The negative ideal solution is: Then calculate the Euclidean distance between each filler to be evaluated and the positive ideal solution and the negative ideal solution. The positive ideal solution distance is: The negative ideal solution distance is: Finally, calculate the comprehensive evaluation score of each filler to be evaluated The comprehensive evaluation scores are ranked to obtain the evaluation results of the fillers of the sewage treatment infiltration system, so as to select the fillers with the best performance.

10. A method for evaluating fillers in a sewage treatment infiltration system according to claim 6, characterized in that: In step 2, the sewage connected through the water inlet (4) is fed with a hydraulic load not exceeding 0.03 m / h, and the water flowing out of the water outlet (5) is stored in a water storage bottle on a daily basis.

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