A method and system for recycling wastewater from plastic pellet production

Abstract

This application discloses a method and system for recycling wastewater from plastic pellet production, relating to the field of wastewater treatment technology. The method includes: acquiring fluctuation curves of dissolved oxygen, chemical oxygen demand (COD), and reagent concentration during multiple wastewater treatment processes over a historical period; calculating a first degree of consistency between the changes in dissolved oxygen and COD, and a second degree of consistency between COD and reagent concentration, based on each fluctuation curve; calculating a reference level of historical treatment data corresponding to each wastewater treatment process based on the first and second degree of consistency; extracting the maximum reference level from each reference level; determining the reagent addition time point based on the wastewater quality corresponding to the maximum reference level and the wastewater quality of the current cycle; and treating the wastewater of the current cycle using the historical treatment data corresponding to the maximum reference level after the reagent addition time point. This application improves wastewater treatment efficiency.

Description

Technical Field

[0001] This application relates to the field of wastewater treatment technology, and in particular to a method and system for recycling wastewater from plastic pellet production. Background Technology

[0002] Wastewater from plastic pellet production mainly originates from the washing, crushing, and pelleting of waste plastics. Its composition is complex and its pollution load is high. Currently, traditional combined processes such as coagulation sedimentation + biological contact oxidation are gradually becoming the mainstream methods for recycling wastewater from plastic pellet production.

[0003] Currently, in the process of recycling wastewater from plastic pellet production using combined processes, constant dosing and aeration control are usually adopted. For example, during the dosing process, the dosing is usually done manually based on experience at fixed times and in fixed quantities. This not only results in a large amount of chemicals being used, but also makes it difficult to make precise adjustments based on real-time changes in water quality. The existing method has the problems of excessive energy consumption and poor wastewater treatment effect. Summary of the Invention

[0004] The main purpose of this application is to provide a method and system for recycling wastewater from plastic pellet production, aiming to solve the technical problems of relying on manual experience to add chemicals at regular intervals and in specific quantities in related technologies. This not only results in large amounts of chemicals being used, but also makes it difficult to make precise adjustments according to real-time changes in water quality, leading to excessive energy consumption and poor wastewater treatment effects.

[0005] To achieve the above objectives, this application provides a method for recycling wastewater from plastic pellet production, comprising:

[0006] Obtain the fluctuation curves of dissolved oxygen, chemical oxygen demand and reagent concentration during multiple wastewater treatment processes within a historical time period;

[0007] Based on each fluctuation curve, the first degree of consistency between the changes in dissolved oxygen and chemical oxygen demand, and the second degree of consistency between chemical oxygen demand and reagent concentration were calculated respectively.

[0008] Based on the first and second degree of consistency, the reference level of historical treatment data corresponding to each wastewater treatment process is calculated.

[0009] Extract the maximum value of each reference level, and determine the time point for adding the reagent based on the comparison data between the wastewater quality corresponding to the maximum value of the reference level and the wastewater quality of the current cycle;

[0010] After the reagent is added, the wastewater for the current cycle is treated using historical treatment data corresponding to the maximum reference level.

[0011] In one possible embodiment of this application, based on each fluctuation curve, a first degree of consistency between the changes in dissolved oxygen and chemical oxygen demand (COD), and a second degree of consistency between COD and reagent concentration are calculated, including:

[0012] Based on the fluctuation curves of dissolved oxygen and chemical oxygen demand, the first degree of consistency between the changes in dissolved oxygen and chemical oxygen demand is calculated.

[0013] Based on the fluctuation curves of chemical oxygen demand (COD) and reagent concentration, the second degree of consistency between COD and reagent concentration was calculated.

[0014] In one possible embodiment of this application, a first degree of consistency between the changes in dissolved oxygen and chemical oxygen demand is calculated based on the fluctuation curves of dissolved oxygen and chemical oxygen demand, including:

[0015] Determine the degree of similarity between the fluctuation curve of dissolved oxygen and the fluctuation curve of chemical oxygen demand;

[0016] Based on the degree of similarity, the first degree of consistency between the changes in dissolved oxygen and chemical oxygen demand was calculated.

[0017] In one possible embodiment of this application, a second degree of consistency between chemical oxygen demand (COD) and reagent concentration is calculated based on the fluctuation curves of COD and reagent concentration, including:

[0018] For any wastewater treatment process, the chemical oxygen demand (COD) at the time point when the chemical dosing begins in the current wastewater treatment process is set as the COD threshold.

[0019] The portion of the chemical oxygen demand (COD) fluctuation curve after the COD threshold is divided into reagent concentration change curves.

[0020] Based on the first slope value of the drug concentration change curve and the second slope value of the drug concentration fluctuation curve, the second degree of consistency between chemical oxygen demand and drug concentration is calculated.

[0021] In one possible implementation of this application, after calculating the reference level of historical treatment data corresponding to each wastewater treatment process based on a first consistency level and a second consistency level, the method further includes:

[0022] Obtain the treatment duration of each wastewater treatment process within a historical time period, as well as the remaining chemical oxygen demand after each wastewater treatment process is completed;

[0023] Based on the remaining chemical oxygen demand and treatment time, the treatment effect of each wastewater treatment process is calculated.

[0024] The reference level is adjusted based on the quality of the processing effect.

[0025] In one possible implementation of this application, the reference level is corrected based on the degree of processing effectiveness, including:

[0026] Multiply the processing performance score by the reference score to obtain the first product;

[0027] The first product is used as the corrected reference level.

[0028] In one possible embodiment of this application, before obtaining the fluctuation curves of dissolved oxygen, chemical oxygen demand, and reagent concentration during multiple wastewater treatment processes over a historical period, the method further includes:

[0029] Acquire influent and effluent flow data during the wastewater pretreatment process;

[0030] The effectiveness of wastewater pretreatment is calculated based on influent and effluent flow data.

[0031] Based on the effectiveness, determine the initial values ​​of dissolved oxygen and reagent concentration required for wastewater treatment;

[0032] After the reagent addition time point, the step of treating the wastewater for the current cycle based on historical treatment data corresponding to the maximum reference severity also includes:

[0033] After the reagent is added, the wastewater for the current cycle is treated based on historical treatment data corresponding to the reference level, the initial value of dissolved oxygen, and the initial value of reagent concentration.

[0034] In one possible implementation of this application, the effectiveness of wastewater pretreatment is calculated based on influent flow rate data and effluent flow rate data, including:

[0035] Based on the influent flow rate data, the first fluctuation amplitude and influent flow velocity characteristics when wastewater enters are determined.

[0036] Based on the effluent flow rate data, the second fluctuation amplitude and effluent flow velocity characteristics at the wastewater outflow are determined.

[0037] Based on the first fluctuation amplitude, the second fluctuation amplitude, the influent flow velocity characteristics, and the effluent flow velocity characteristics, the effectiveness of wastewater pretreatment is calculated, whereby the effectiveness is used to characterize the treatment effect of wastewater pretreatment.

[0038] In one possible implementation of this application, determining the initial values ​​of dissolved oxygen and reagent concentration required for wastewater treatment based on the degree of effectiveness includes:

[0039] Based on the effectiveness and the reference value of dissolved oxygen required for wastewater treatment, the initial value of dissolved oxygen is calculated.

[0040] Based on the effectiveness and the reference values ​​of the reagent concentration required for wastewater treatment, the initial value of the reagent concentration is calculated.

[0041] This application also provides a system for recycling wastewater from plastic pellet production. The system includes a memory, a processor, and a computer program stored in the memory and running on the processor. When the processor executes the computer program, it implements the steps of the above-described method for recycling wastewater from plastic pellet production.

[0042] This application provides a method and system for recycling wastewater from plastic pellet production. Compared with related technologies that rely on manual experience to add chemicals at fixed times and in fixed quantities, which not only involves large amounts of chemicals but also makes it difficult to make precise adjustments based on real-time changes in water quality, resulting in excessive energy consumption and poor wastewater treatment effects, this application obtains the fluctuation curves of dissolved oxygen, chemical oxygen demand (COD), and chemical concentration during multiple wastewater treatment processes over a historical period. Based on these fluctuation curves, a first degree of consistency between dissolved oxygen and COD, and a second degree of consistency between COD and chemical concentration, are calculated. Furthermore, based on the first and second degrees of consistency, the efficiency of each treatment process is calculated. The reference level of historical treatment data corresponding to the wastewater treatment process is determined. When the reference level meets the preset conditions, the time point for adding the chemical oxygen demand (COD) agent is determined based on the comparison data between the wastewater quality corresponding to the reference level and the wastewater quality of the current cycle. This achieves the effect of timely addition of the agent. After the agent addition time point, the wastewater of the current cycle is treated using the historical treatment data corresponding to the reference level. Then, the wastewater treatment agent is added at the accurate time point, and the wastewater treatment data is precisely adjusted based on the wastewater treatment situation during the process and the real-time changes in water quality. This reduces the energy consumption required for wastewater treatment and improves the wastewater treatment effect. Attached Figure Description

[0043] Figure 1 This is a schematic flowchart of the first embodiment of the method for recycling wastewater from plastic pellet production according to this application.

[0044] Figure 2 This is a schematic flowchart of the second embodiment of the method for recycling wastewater from plastic pellet production according to this application.

[0045] Figure 3 This is a schematic diagram of the device structure of the hardware operating environment involved in the embodiments of this application. Detailed Implementation

[0046] It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0047] This application provides a method for recycling wastewater from plastic pellet production. In the first embodiment of this method, refer to... Figure 1 The methods include:

[0048] Step S10: Obtain the fluctuation curves of dissolved oxygen, chemical oxygen demand and reagent concentration during multiple wastewater treatment processes within a historical time period.

[0049] Step S20: Based on each fluctuation curve, calculate the first degree of consistency between the changes in dissolved oxygen and chemical oxygen demand, and the second degree of consistency between chemical oxygen demand and reagent concentration.

[0050] Step S30: Based on the first consistency level and the second consistency level, calculate the reference level of the historical treatment data corresponding to each wastewater treatment process;

[0051] Step S40: Extract the maximum value of each reference level, and determine the time point for adding the reagent based on the comparison data between the wastewater quality corresponding to the maximum value of the reference level and the wastewater quality of the current cycle.

[0052] Step S50: After the reagent is added, the wastewater of the current cycle is treated using historical treatment data corresponding to the maximum reference level.

[0053] This embodiment aims to: accurately adjust wastewater treatment data based on the wastewater treatment situation during historical time periods and with reference to real-time changes in water quality, thereby reducing the energy consumption required for wastewater treatment and improving the wastewater treatment effect.

[0054] The specific steps are as follows:

[0055] Step S10: Obtain the fluctuation curves of dissolved oxygen, chemical oxygen demand and reagent concentration during multiple wastewater treatment processes within a historical time period.

[0056] As an example, the method for recycling wastewater from plastic pellet production can be applied to a wastewater recycling device for plastic pellet production, which belongs to the category of wastewater recycling equipment for plastic pellet production.

[0057] As an example, the wastewater recycling method for plastic pellet production can also be applied to a wastewater recycling system for plastic pellet production. This system includes a pretreatment unit, a main treatment unit, a deep treatment and reuse unit, and an intelligent control unit. The functional descriptions of each unit are as follows:

[0058] 1. Pretreatment unit: This is the first barrier for plastic particle wastewater entering the wastewater system. It uses physical means such as a bar screen filtration system to intercept large impurities, creating a suitable environment for subsequent core purification stages.

[0059] 2. Main treatment unit: It degrades pollutants through the synergistic action of biology and chemistry. It is divided into two parts: a biochemical treatment module and an advanced oxidation module. Flow sensors are installed at the outlet and inlet to collect the flow rate of wastewater in real time. The sampling frequency is once every 10 seconds.

[0060] 2.1 Biochemical Reaction Module: Composed of an anaerobic tank and an aerobic tank. The anaerobic tank uses an IC reactor, and a three-phase separator is used to separate biogas, sludge, and water. The aerobic tank is equipped with a membrane aeration bioreactor and a hollow fiber membrane. The activated fouling in the membrane aeration bioreactor relies on DO (dissolved oxygen) provided by the aeration system for metabolic activities. The airflow disturbance on the surface of the hollow fiber membrane ensures the degradation efficiency of organic matter by microorganisms. In actual operation, the DO content in the aerobic tank is measured in real time by a dissolved oxygen meter, and the power of the aeration blower is adjusted when necessary.

[0061] 2.2 Advanced Oxidation Module: After biochemical treatment, the COD (Chemical Oxygen Demand) in the wastewater needs to be reduced to below 300 mg / L. If the COD in the wastewater after biochemical treatment is too high, or if the COD in the wastewater entering the biochemical reaction module is too high, the Fenton oxidation device needs to be started to reduce the COD to a reasonable level by adding reagents to the wastewater.

[0062] 3. Advanced treatment and reuse unit: The wastewater is chemically cleaned by removing colloidal and macromolecular organic matter through a membrane separation system. After cleaning, a disinfection unit is set up to disinfect the wastewater. After disinfection, the treated wastewater is transported to a water storage unit for repeated recycling.

[0063] 4. Intelligent control unit:

[0064] Data acquisition layer: COD online analyzers are installed at the inlet and outlet of the aerobic tank, and DO analyzers are installed inside the tank. The sampling frequency is once every 10 seconds.

[0065] Control and execution layer: Multiple execution devices, including dosing pumps and aeration fans, are driven through the PLC control cabinet, and precise adjustments are made according to the central control instructions.

[0066] As an example, the historical time period can be the past 3 hours or 5 hours. During this period, there will be multiple wastewater treatment processes. Dissolved oxygen is an essential condition for the survival and degradation of organic matter by aerobic microorganisms (such as bacteria in activated sludge). Chemical oxygen demand is a core indicator for measuring the content of organic pollutants in water and is used to represent the pollutant content in wastewater. The reagent concentration can be the concentration of chemicals such as carbon sources, phosphorus removal agents, and flocculants. By using different reagent concentrations, wastewater is treated to remove specific pollutants.

[0067] As an example, the fluctuation curve is obtained by statistically analyzing the changes in dissolved oxygen, chemical oxygen demand, and reagent concentration at various times during multiple wastewater treatment processes, and then plotting the changes at different times to obtain the fluctuation curve.

[0068] Before step S10, which involves obtaining the fluctuation curves of dissolved oxygen, chemical oxygen demand, and reagent concentration during multiple wastewater treatment processes over a historical period, the method further includes:

[0069] Obtain influent and effluent flow data during the wastewater pretreatment process.

[0070] As an example, the wastewater pretreatment process is completed by a pretreatment unit. First, in the pretreatment unit, the wastewater passes through a bar screen filtration system and other physical means to remove large impurities before entering the main treatment unit. The pretreatment unit includes an inlet and an outlet, with the outlet connected to the main treatment unit.

[0071] As an example, influent flow rate data can be the flow velocity data and flow velocity fluctuations of wastewater entering from the inlet. Similarly, effluent flow rate data can be the flow velocity data and flow velocity fluctuations of wastewater flowing out from the outlet.

[0072] The effectiveness of wastewater pretreatment is calculated based on influent and effluent flow data.

[0073] As an example, by calculating the changes in flow rate data when wastewater enters and exits, the effectiveness of the plastic pellet production wastewater entering the main treatment unit can be determined, that is, the degree of filtration of the wastewater by the pretreatment unit can be determined, thereby determining how much reagent the main treatment unit needs to add when treating the remaining wastewater.

[0074] The step of calculating the effectiveness of wastewater pretreatment based on influent and effluent flow data includes:

[0075] Based on the influent flow rate data, the first fluctuation amplitude and influent flow velocity characteristics when wastewater enters are determined.

[0076] As an example, based on the influent flow rate data, the velocity fluctuation curve of the inlet during the current wastewater treatment process is determined and denoted as fluctuation curve 1. The first fluctuation amplitude is the fluctuation amplitude of fluctuation curve 1 when the wastewater enters from the inlet, and the influent velocity characteristic is the average of all velocities on fluctuation curve 1.

[0077] Based on the effluent flow rate data, the second fluctuation amplitude and effluent flow velocity characteristics during wastewater outflow are determined.

[0078] As an example, based on the effluent flow rate data, the velocity fluctuation curve at the effluent outlet during the current wastewater treatment process is determined and denoted as fluctuation curve 2. The second fluctuation amplitude is the fluctuation amplitude of fluctuation curve 2 when the wastewater flows out of the outlet, and the effluent velocity characteristic is the average of all velocities on fluctuation curve 2.

[0079] Based on the first fluctuation amplitude, the second fluctuation amplitude, the influent flow velocity characteristics, and the effluent flow velocity characteristics, the effectiveness of wastewater pretreatment is calculated, whereby the effectiveness is used to characterize the treatment effect of wastewater pretreatment.

[0080] As an example, the effectiveness of the plastic pellet production wastewater entering the main treatment unit is calculated based on the correlation between the flow velocity characteristics of the outlet and inlet. Specifically, the mathematical formula for the effectiveness α of the plastic pellet production wastewater entering the main treatment unit is:

[0081]

[0082] In the formula, α represents the effectiveness of the plastic pellet production wastewater entering the main treatment unit, norm() represents the normalization function, B1 represents the first fluctuation amplitude of the inlet velocity fluctuation curve, B2 represents the second fluctuation amplitude of the outlet velocity fluctuation curve, +1 is to avoid the denominator being 0, e () Let |B1| represent an exponential function with base e, where A1 represents the inlet flow velocity characteristic and A2 represents the outlet flow velocity characteristic. A smaller value for |B1-B2| indicates more consistent flow velocity fluctuations at the inlet and outlet, resulting in more stable wastewater treatment. A larger value for (A2-A1) indicates a greater variation in wastewater flow velocity at the outlet compared to the inlet, leading to better wastewater treatment performance in the pretreatment unit.

[0083] In other words, the larger the value of α, the more effective the wastewater from plastic pellet production entering the main unit is, and the better the wastewater treatment effect of the pretreatment unit will be.

[0084] Based on the effectiveness, determine the initial values ​​of dissolved oxygen and reagent concentration required for wastewater treatment.

[0085] As an example, for plastic pellet production wastewater entering the main treatment unit, the lower the corresponding effectiveness level, the higher the treatment difficulty in the main treatment unit. Therefore, based on the effectiveness level of treatment in the pretreatment unit, the initial values ​​of dissolved oxygen and reagent concentration required for wastewater treatment in the main treatment unit are calculated.

[0086] As an example, the initial value of dissolved oxygen is the initial value of dissolved oxygen required by the main treatment unit; similarly, the initial value of reagent concentration is the initial value of reagent concentration required by the main treatment unit.

[0087] The steps for determining the initial dissolved oxygen and reagent concentration required for wastewater treatment based on effectiveness include:

[0088] Based on the effectiveness and the reference value of dissolved oxygen required for wastewater treatment, the initial value of dissolved oxygen was calculated.

[0089] Based on the effectiveness and the reference values ​​of the reagent concentration required for wastewater treatment, the initial value of the reagent concentration is calculated.

[0090] As an example, the formula for calculating the initial dissolved oxygen value β1 can be:

[0091]

[0092] In the formula, β1 represents the initial dissolved oxygen value in the main treatment unit, D is the theoretical reference value of dissolved oxygen required in the main treatment unit, i.e., the dissolved oxygen reference value; α represents the effectiveness of the treatment of plastic pellet production wastewater entering the main treatment unit. This represents the correction parameter value for dissolved oxygen (an empirical value).

[0093] As an example, the initial value of the reagent concentration is calculated in the same way as the initial value of dissolved oxygen. Simply replace the reference value of dissolved oxygen with the reference value of reagent concentration, and replace the correction parameter value of dissolved oxygen with the correction parameter value of reagent concentration. The reference value of dissolved oxygen and the correction parameter value of dissolved oxygen can be extracted from the database, and the reference value of reagent concentration and the correction parameter value of reagent concentration are obtained in the same way.

[0094] As an example, when the value of (0.5-α) is greater than 0, it indicates that the effectiveness of the plastic pellet production wastewater entering the main treatment unit is poor, and the initial value of dissolved oxygen required in the main treatment unit should be larger, and vice versa.

[0095] After the reagent addition time point, the step of treating the wastewater for the current cycle based on historical treatment data corresponding to the maximum reference severity also includes:

[0096] After the reagent is added, the wastewater for the current cycle is treated based on the historical treatment data corresponding to the maximum reference level, the initial dissolved oxygen value, and the initial reagent concentration value.

[0097] As an example, the time point for adding the reagent is the time point when the reagent needs to be added to the wastewater. As the biochemical reaction proceeds, when the chemical oxygen demand of the wastewater reaches a certain level during the treatment process, the dosing pump will be started to add the reagent to the wastewater. This time point for adding the reagent is the time point for adding the reagent.

[0098] As an example, based on the initial values ​​of dissolved oxygen and reagent concentration, as well as historical treatment data or parameters from each wastewater treatment process, the wastewater treatment parameters for the current cycle are determined, thereby treating the wastewater for the current cycle.

[0099] Step S20: Based on each fluctuation curve, calculate the first degree of consistency between the changes in dissolved oxygen and chemical oxygen demand, and the second degree of consistency between chemical oxygen demand and reagent concentration.

[0100] As an example, the first degree of consistency refers to the degree of consistency between the curves showing changes in dissolved oxygen and chemical oxygen demand, i.e., similarity. Similarly, the second degree of consistency refers to the degree of consistency between the curves showing changes in chemical oxygen demand and reagent concentration.

[0101] The step S20, which calculates the first degree of consistency between the changes in dissolved oxygen and chemical oxygen demand (COD) and the second degree of consistency between COD and reagent concentration based on each fluctuation curve, further includes steps S21 to S22, including:

[0102] Step S21: Based on the fluctuation curves of dissolved oxygen and chemical oxygen demand, calculate the first degree of consistency between the changes in dissolved oxygen and chemical oxygen demand.

[0103] As an example, after determining the fluctuation curves of dissolved oxygen and chemical oxygen demand, the first degree of consistency between the changes in dissolved oxygen and chemical oxygen demand is calculated based on the data sequences of the two fluctuation curves.

[0104] Step S21 further includes:

[0105] Determine the degree of similarity between the fluctuation curve of dissolved oxygen and the fluctuation curve of chemical oxygen demand;

[0106] As an example, the degree of similarity between the fluctuation curve of dissolved oxygen and the fluctuation curve of chemical oxygen demand can be obtained by calculating the DTW (Dynamic Time Warping) distance of the data sequences corresponding to the two fluctuation curves.

[0107] Based on the degree of similarity, the first degree of consistency between the changes in dissolved oxygen and chemical oxygen demand was calculated.

[0108] As an example, taking the m-th processing step as an example, the first consistency level ρ m The calculation method can be:

[0109]

[0110] In the formula, ρ m This indicates the degree of consistency between the changes in COD and DO during the m-th treatment. DTW(S) cod S do The ) represents the DTW distance between the COD fluctuation curve and the DO fluctuation curve, i.e., the degree of similarity. +1 is used to prevent the denominator from being zero. S cod The curve representing the fluctuation of chemical oxygen demand (COD), S do The curve representing the fluctuation of dissolved oxygen (DO).

[0111] When the calculated ρ m The larger the value, the more similar the changes in the two fluctuation curves are during the treatment of wastewater from plastic pellet production, indicating that the adjustment time of DO concentration with changes in COD is higher.

[0112] Step S22: Based on the fluctuation curves of chemical oxygen demand and reagent concentration, calculate the second degree of consistency between chemical oxygen demand and reagent concentration.

[0113] As an example, after determining the fluctuation curves of chemical oxygen demand (COD) and reagent concentration, the second degree of consistency between the changes in dissolved oxygen and COD is calculated based on the changes in the slopes of the two fluctuation curves.

[0114] Step S22 further includes:

[0115] For any wastewater treatment process, the chemical oxygen demand (COD) at the time point when the chemical dosing begins in the current wastewater treatment process is set as the COD threshold.

[0116] As an example, as the biochemical reaction proceeds, when the COD (chemical oxygen demand) content is high during the treatment process, the dosing pump will be activated to add chemicals to the wastewater. Therefore, the time when the dosing starts during the m-th treatment process can be obtained, and the COD value corresponding to the time point when the dosing starts can be recorded as the COD threshold, which is also the chemical oxygen demand threshold.

[0117] The portion of the chemical oxygen demand (COD) fluctuation curve after the COD threshold is divided into reagent concentration change curves.

[0118] As an example, the COD fluctuation curve during the m-th treatment is divided into two parts according to the COD threshold, and they are denoted as COD fluctuation curve 1 and COD fluctuation curve 2 in chronological order. COD fluctuation curve 2 is the drug concentration change curve, that is, the change curve after the drug is added.

[0119] As an example, since the COD content gradually decreases as the drug concentration increases, the consistency between the drug concentration change curve and the drug concentration change is calculated first.

[0120] Based on the first slope value of the drug concentration change curve and the second slope value of the drug concentration fluctuation curve, the second degree of consistency between chemical oxygen demand and drug concentration is calculated.

[0121] As an example, taking the m-th treatment process as an example, the second degree of consistency θ between the change in COD and the change in reagent concentration. m The mathematical formula is:

[0122]

[0123] In the formula, θ m This represents the second degree of consistency between the changes in COD and the changes in reagent concentration during the m-th treatment, l cod Let l0 represent the first slope value of the fitted curve corresponding to the drug concentration change curve (expressed as the average slope of all points on the fitted curve), l0 represent the second slope value of the fitted curve of the drug concentration fluctuation curve, || represents the absolute value function, and norm() is the normalization function. Since, ideally, COD changes and drug concentration changes are inversely proportional, |l0 cod The closer the value of -l0| is to |l cod |+|l0| indicates that the more closely the relationship is satisfied, the higher the corresponding θ. m The larger the value, the greater the consistency between the COD change and the reagent concentration change during the m-th treatment.

[0124] Step S30: Based on the first consistency level and the second consistency level, calculate the reference level of the historical treatment data corresponding to each wastewater treatment process.

[0125] As an example, for the m-th wastewater treatment process, the higher the consistency between the changes in COD and DO during the wastewater treatment process, and the higher the consistency between the changes in COD and the changes in reagent concentration, the more worthy the adjustment of various parameters in the m-th treatment process is of reference.

[0126] As an example, taking the m-th wastewater treatment process as an example, the reference value γ of various historical data in the current treatment process is... m for:

[0127] γ m =ρm×θ m

[0128] In the formula, γ m ρm represents the reference level of historical data in the m-th processing step, ρm represents the first degree of consistency between COD and DO changes in the m-th processing step, and θ represents the first degree of consistency. m This indicates the second degree of consistency between the changes in COD and the changes in reagent concentration during the m-th treatment.

[0129] Step S40: Extract the maximum value of each reference level. Based on the comparison data between the wastewater quality corresponding to the maximum value of the reference level and the wastewater quality of the current cycle, determine the time point for adding the reagent.

[0130] As an example, the greater the degree of reference, the more valuable the historical treatment data in the wastewater treatment process is to refer to. Historical treatment data includes dissolved oxygen concentration and reagent concentration.

[0131] As an example, during treatment, the wastewater quality corresponding to the reference level is first compared with the water quality of the current cycle. When the water quality is different, the chemical oxygen demand (COD) threshold corresponding to the time point when the reagent needs to be added is also different. This can be achieved by weighting the COD thresholds from multiple treatment processes over a historical period, where the weight is the reference level corresponding to each wastewater treatment process. Thus, the COD threshold for the current cycle is obtained. When the COD in the wastewater of the current cycle is detected to be greater than the COD threshold, the reagent is added. The time when the reagent is added is called the reagent addition time point.

[0132] As an example, another way to determine the timing of adding the reagent is to compare the current chemical oxygen demand (COD) in the water with the COD in the wastewater corresponding to the maximum reference level, calculate the ratio between the two, and multiply the ratio by the COD threshold corresponding to the maximum reference level to obtain the COD threshold for the current cycle, thereby determining the timing of adding the reagent.

[0133] Step S50: After the reagent is added, the wastewater of the current cycle is treated using historical treatment data corresponding to the maximum reference level.

[0134] As an example, after determining the time point for adding the reagent, the historical treatment data corresponding to the maximum reference level is used as a reference. This historical treatment data includes the required reagent concentration and dissolved oxygen content, as well as the curve showing the change between the two. In the current round, the reagent concentration and dissolved oxygen content are added according to the historical treatment data corresponding to the maximum reference level, which can achieve a better wastewater treatment effect.

[0135] This application provides a method for recycling wastewater from plastic pellet production. Compared with related technologies that rely on manual experience to add chemicals at fixed times and in fixed quantities, which not only involves large amounts of chemicals but also makes it difficult to make precise adjustments based on real-time changes in water quality, resulting in excessive energy consumption and poor wastewater treatment effects, this application obtains the fluctuation curves of dissolved oxygen, chemical oxygen demand (COD), and chemical concentration during multiple wastewater treatment processes over a historical period. Based on these fluctuation curves, a first degree of consistency between the changes in dissolved oxygen and COD, and a second degree of consistency between COD and chemical concentration, are calculated. Furthermore, based on the first and second degrees of consistency, the wastewater treatment efficiency for each treatment process is calculated. The reference level of historical treatment data corresponding to the water treatment process is determined. When the reference level meets the preset conditions, the time point for adding the chemical oxygen demand (COD) agent is determined based on the comparison data between the wastewater quality corresponding to the reference level and the wastewater quality of the current cycle. This achieves the effect of timely addition of the agent. After the agent addition time point, the wastewater of the current cycle is treated using the historical treatment data corresponding to the reference level. Then, the agent for treating the wastewater is added at the accurate time point. Based on the wastewater treatment situation during the wastewater treatment process, the wastewater treatment data is precisely adjusted with reference to the real-time changes in water quality. This reduces the energy consumption required for wastewater treatment and improves the wastewater treatment effect.

[0136] Furthermore, referring to Figure 2 Based on the first embodiment of this application, another embodiment of this application is provided. In this embodiment, after step S30 of calculating the reference level of historical treatment data corresponding to each wastewater treatment process based on the first consistency level and the second consistency level, the method further includes:

[0137] Step S300: Obtain the treatment time of each wastewater treatment process within the historical time period, as well as the remaining chemical oxygen demand after each wastewater treatment process is completed.

[0138] As an example, the treatment time for each wastewater treatment process is not fixed and will be dynamically adjusted according to different water quality conditions. Taking the m-th wastewater treatment process as an example, the shorter the treatment time in the m-th treatment process and the lower the chemical oxygen demand (COD) of the wastewater at the effluent after treatment, the better the treatment effect in the m-th treatment process. Therefore, by using the treatment time and COD of each wastewater treatment process, the quality of treatment effect for each wastewater treatment process can be determined, and the reference level can be corrected based on the quality of treatment effect.

[0139] As an example, residual chemical oxygen demand (COD) is the amount of chemical oxygen demand remaining in the wastewater after each wastewater treatment process.

[0140] Step S310: Based on the remaining chemical oxygen demand and treatment time, calculate the treatment effect quality of each wastewater treatment process.

[0141] As an example, taking the m-th wastewater treatment process as an example, the treatment effect quality σ m The mathematical formula is:

[0142]

[0143] In the formula, σ m T represents the quality of the wastewater treatment process in the m-th treatment phase. m This represents the treatment time in the m-th wastewater treatment process. V represents the total treatment time of all wastewater treatment processes. cod This represents the COD value after the m-th treatment, which is also the remaining chemical oxygen demand. σ represents the sum of the COD values ​​after all M processing steps, therefore σ m The larger the value, the better the processing effect in the m-th processing step.

[0144] Step S320: Correct the reference level based on the quality of the processing effect.

[0145] The step S320, which corrects the reference level based on the quality of the processing effect, includes:

[0146] Multiply the processing performance score by the reference score to obtain the first product;

[0147] The first product is used as the corrected reference level.

[0148] As an example, the reference level of various historical data in the m-th processing step is adjusted based on the quality of the processing effect in the m-th processing step, and then the reference level τ of the adjusted historical data in the m-th processing step is obtained. m for:

[0149] τ m =γ m ×σ m

[0150] In the formula, τ m γ represents the reference level of the corrected historical data in the m-th wastewater treatment process. m σ represents the reference level of various historical data in the m-th wastewater treatment process. m The degree of excellence of the treatment effect in the m-th wastewater treatment process is represented by the first product, which is then used as the corrected reference degree.

[0151] As an example, by calculating the quality of treatment effect in each wastewater treatment process and correcting each reference level based on the quality of treatment effect, the reference level is made more accurate, thereby improving the referenceability of the treatment data for each wastewater treatment process and further improving the wastewater treatment effect.

[0152] As an example, after correcting the reference level for each wastewater treatment process, the maximum reference level among the corrected reference levels is selected, and the wastewater of the current round is treated using the historical treatment data corresponding to the maximum reference level.

[0153] In this embodiment, the treatment effect quality is calculated for each wastewater treatment process, and the reference levels are corrected based on the treatment effect quality, thereby making the reference levels more accurate.

[0154] Reference Figure 3 , Figure 3 This is a schematic diagram of the device structure of the hardware operating environment involved in the embodiments of this application.

[0155] like Figure 3 As shown, the wastewater recycling equipment for plastic pellet production may include: a processor 1001, a memory 1005, and a communication bus 1002. The communication bus 1002 is used to realize the connection and communication between the processor 1001 and the memory 1005.

[0156] Optionally, the wastewater recycling equipment for plastic pellet production may also include a user interface, a network interface, a camera, RF (Radio Frequency) circuitry, sensors, a WiFi module, etc. The user interface may include a display screen and an input submodule such as a keyboard; optional user interfaces may also include standard wired or wireless interfaces. The network interface may include standard wired or wireless interfaces (such as a Wi-Fi interface).

[0157] Those skilled in the art will understand that Figure 3 The structure of the wastewater recycling equipment shown in the figure does not constitute a limitation on the wastewater recycling equipment for plastic pellet production. It may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0158] like Figure 3As shown, the memory 1005, serving as a storage medium, may include an operating system, a network communication module, and a program for recycling wastewater from plastic pellet production. The operating system is a program that manages and controls the hardware and software resources of the wastewater recycling equipment, supporting the operation of the wastewater recycling program and other software and / or programs. The network communication module is used to enable communication between the various components within the memory 1005, as well as communication with other hardware and software in the wastewater recycling system.

[0159] exist Figure 3 In the wastewater recycling equipment for plastic pellet production shown, the processor 1001 is used to execute the wastewater recycling program for plastic pellet production stored in the memory 1005 to implement the steps of any of the above-mentioned wastewater recycling methods for plastic pellet production.

[0160] The specific implementation method of the wastewater recycling equipment for plastic pellet production in this application is basically the same as the embodiments of the above-mentioned wastewater recycling method for plastic pellet production, and will not be repeated here.

[0161] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or system that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or system. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or system that includes that element.

[0162] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0163] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods of the various embodiments of this application.

[0164] The above are merely preferred embodiments of this application and do not limit the scope of this application. Any equivalent structural or procedural transformations made based on the description and drawings of this application, or direct or indirect applications in other related technical fields, are similarly included within the scope of protection of this application.

[0165] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0166] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

Claims

1. A method for recycling wastewater from plastic pellet production, characterized in that, The method includes: Acquire influent and effluent flow data during the wastewater pretreatment process; Based on the influent flow rate data and the effluent flow rate data, the effectiveness of wastewater pretreatment is calculated. Based on the aforementioned level of effectiveness, determine the initial values ​​of dissolved oxygen and reagent concentration required for wastewater treatment. Obtain the fluctuation curves of dissolved oxygen, chemical oxygen demand and reagent concentration during multiple wastewater treatment processes within a historical time period; Based on each of the aforementioned fluctuation curves, the first degree of consistency between the changes in dissolved oxygen and chemical oxygen demand, and the second degree of consistency between chemical oxygen demand and reagent concentration are calculated respectively. The calculation of the first degree of consistency between the changes in dissolved oxygen and chemical oxygen demand (COD) and the second degree of consistency between COD and reagent concentration, based on each of the fluctuation curves, includes: Determine the degree of similarity between the fluctuation curve of dissolved oxygen and the fluctuation curve of chemical oxygen demand; Based on the degree of similarity, a first degree of consistency between the changes in dissolved oxygen and chemical oxygen demand is calculated; For any wastewater treatment process, the chemical oxygen demand (COD) at the time point when the chemical dosing begins in the current wastewater treatment process is set as the COD threshold. The portion of the chemical oxygen demand (COD) fluctuation curve after the COD threshold is divided into reagent concentration change curves. Based on the first slope value of the drug concentration change curve and the second slope value of the drug concentration fluctuation curve, the second degree of consistency between the chemical oxygen demand and the drug concentration is calculated. Based on the first degree of consistency and the second degree of consistency, the reference level of historical treatment data corresponding to each wastewater treatment process is calculated. Extract the maximum value of each reference level, and determine the time point for adding the reagent based on the comparison data between the wastewater quality corresponding to the maximum value of the reference level and the wastewater quality of the current cycle; After the time point when the reagent is added, the wastewater of the current cycle is treated based on the historical treatment data corresponding to the maximum reference level, the initial value of dissolved oxygen, and the initial value of reagent concentration.

2. The method for recycling wastewater from plastic pellet production as described in claim 1, characterized in that, After calculating the reference level of historical treatment data corresponding to each wastewater treatment process based on the first consistency level and the second consistency level, the method further includes: Obtain the treatment duration of each wastewater treatment process within a historical time period, as well as the remaining chemical oxygen demand after each wastewater treatment process is completed; Based on the remaining chemical oxygen demand and the treatment time, the treatment effect quality of each wastewater treatment process is calculated. The reference level is corrected based on the degree of excellence of the processing effect.

3. The method for recycling wastewater from plastic pellet production as described in claim 2, characterized in that, The process of correcting the reference level based on the quality of the processing effect includes: Multiply the degree of excellence of the processing effect by the degree of reference to obtain the first product; The first product is used as the corrected reference level.

4. The method for recycling wastewater from plastic pellet production as described in claim 1, characterized in that, The calculation of the effectiveness of wastewater pretreatment based on the influent flow rate data and the effluent flow rate data includes: Based on the influent flow rate data, the first fluctuation amplitude and influent flow velocity characteristics when wastewater enters are determined. Based on the effluent flow rate data, the second fluctuation amplitude and effluent flow velocity characteristics at the time of wastewater outflow are determined. Based on the first fluctuation amplitude, the second fluctuation amplitude, the influent flow velocity characteristics, and the effluent flow velocity characteristics, the effectiveness of wastewater pretreatment is calculated, wherein the effectiveness is used to characterize the treatment effect of wastewater pretreatment.

5. The method for recycling wastewater from plastic pellet production as described in claim 1, characterized in that, The determination of the initial dissolved oxygen and reagent concentration required for wastewater treatment based on the aforementioned effectiveness includes: Based on the aforementioned level of effectiveness and the reference value of dissolved oxygen required for wastewater treatment, the initial value of dissolved oxygen is calculated. Based on the aforementioned level of effectiveness and the reference values ​​for reagent concentration required for wastewater treatment, the initial value of reagent concentration is calculated.

6. A system for recycling wastewater from plastic pellet production, characterized in that, The system includes a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that the processor executes the computer program to implement the steps of the method as described in any one of claims 1 to 5.

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