A method, device and system for filtering and purifying comprehensive wastewater

Abstract

The application relates to the technical field of sewage treatment, in particular to a filtering and purifying method, device and system for comprehensive wastewater. The method comprises the following steps: obtaining pretreated wastewater through a pretreatment operation; obtaining first-stage treated wastewater through flocculant precipitation; obtaining second-stage treated wastewater through an activated sludge method and sludge-water separation; in the activated sludge method treatment, an aeration tank is divided into regions, temperature, salinity and dissolved oxygen are collected, an influence weight is determined based on the correlation of temperature, salinity and dissolved oxygen, a comprehensive influence weight is determined based on time difference, the influence weight and fluctuation, and the activated sludge method is completed based on the aeration threshold adjustment; and the second-stage treated wastewater is filtered after being placed in a buffer tank to complete the purification of the wastewater. The application improves the wastewater treatment precision.

Description

Technical Field

[0001] This application relates to the field of wastewater treatment technology, specifically to a comprehensive wastewater filtration and purification method, equipment, and system. Background Technology

[0002] With the rapid development of industrialization and urbanization, water pollution has become increasingly serious. Wastewater is generally generated from human production, daily life, or industrial products. If the substances in wastewater can be recycled or separated, economic benefits can usually be generated. Wastewater refers to water bodies containing waste materials. The pollutants in wastewater are useful substances discharged by humans that mix into the water body, rendering it unusable and thus discarding it. Therefore, the pollutants in wastewater are generally useful substances, and the vast majority of wastewater is generated by industrial production. Filtering and purifying comprehensive wastewater from the industrial sector, which contains complex components such as organic pollutants, inorganic pollutants, and possibly heavy metals and microorganisms, and further reusing the treated water, is an important research direction for water resource protection and recycling.

[0003] Currently, the filtration and purification process for comprehensive industrial wastewater mainly includes pretreatment and tertiary treatment. The pretreatment stage requires coarse and fine screen filtration, grit chambers, and equalization tanks to protect downstream equipment and balance water quality. Primary treatment mainly involves flocculation and sedimentation in sedimentation tanks. Secondary treatment primarily uses activated sludge processes and secondary sedimentation tanks to degrade dissolved organic matter. Tertiary treatment mainly uses V-type filters for filtration and backwashing for deep treatment. After completing the pretreatment and tertiary treatment processes, the treated water is discharged, and the sludge generated in the process is treated. In the operation of comprehensive wastewater treatment, when using the activated sludge process in secondary treatment, dissolved oxygen is maintained by aerating the wastewater in the aeration tank using aeration equipment, allowing aerobic microorganisms to degrade organic matter. However, oxygen levels are affected by factors such as temperature and salinity during the dissolution process. Traditional control methods cannot respond effectively and promptly to fluctuations in temperature and salinity during actual treatment, affecting the control of dissolved oxygen in the aeration tank and resulting in poor filtration and purification effects for the comprehensive wastewater. Summary of the Invention

[0004] To address the technical problem of poor purification effect caused by inadequate dissolved oxygen control in secondary treatment, this application provides a comprehensive wastewater filtration and purification method, equipment, and system. The specific technical solution adopted is as follows:

[0005] Firstly, this application proposes a comprehensive wastewater filtration and purification method, which includes the following steps:

[0006] Industrial wastewater is initially filtered through a screen, and the pre-filtered wastewater is then settled in a grit chamber and the pH value is adjusted to obtain pre-treated wastewater.

[0007] The pretreated wastewater is transported to a sedimentation tank, where flocculants are added for flocculation and sedimentation. The remaining wastewater after sedimentation is used as the primary treated wastewater.

[0008] The primary treated wastewater is sent to an aeration tank, where it is treated using the activated sludge process. The treated mixture is then sent to a secondary sedimentation tank for sludge-water separation to obtain secondary treated wastewater.

[0009] The treatment process using the activated sludge method includes the following steps:

[0010] S1. Divide the aeration tank into several areas according to distance, and collect the influencing factors and dissolved oxygen in each area at each time. The influencing factors include temperature and salinity.

[0011] S2, a sliding window is preset for each time point, and the influence weight of each type of influencing factor at each time point is determined based on the discreteness of the correlation between the influencing factors and dissolved oxygen at each time point within each sliding window.

[0012] S3, based on the time difference between adjacent moments, fluctuations and influence weights of each type of influencing factor, obtain the comprehensive influence weight; after combining the preset initial factor and the comprehensive influence weight, adjust the preset fuzzy subset; use the dissolved oxygen, preset dissolved oxygen setpoint and adjusted fuzzy subset of each region as inputs for fuzzy PID control, and then adjust the preset aeration threshold, and complete the activated sludge process based on the adjusted aeration threshold.

[0013] The secondary treated wastewater is transferred to a buffer tank and allowed to settle. After settling, the wastewater is then filtered to complete the purification process.

[0014] In the aforementioned scheme, this application considers that the dissolved oxygen stability in the aeration tank has a significant impact on the decomposition of organic matter by aerobic microorganisms during the comprehensive wastewater filtration and purification process, thus affecting the wastewater treatment effect. Therefore, an analysis is conducted based on the interference with dissolved oxygen stability. Since fluctuations in temperature and salinity in the aeration tank affect the dissolved oxygen in the wastewater, it is impossible to accurately control the dissolved oxygen in the aeration tank. Temperature and salinity are collected during the treatment process. Considering that increases or decreases in temperature and salinity will inhibit or promote the correlation characteristics of dissolved oxygen to varying degrees, this application analyzes the degree of influence of temperature and salinity fluctuations on dissolved oxygen, obtains the correlation between temperature and salinity and dissolved oxygen under mutual interference, and weights them based on the stability of their correlation. By combining the comprehensive influence weights with the influence of temperature and salinity on dissolved oxygen, a dynamic scaling factor is constructed to dynamically adjust the fuzzy subset of the fuzzy PID control, improving the fine-tuning and convergence speed of the fuzzy PID control, and further improving the accuracy of wastewater treatment.

[0015] In one embodiment, during the pretreatment process, the coarse grid used has a mesh size of 10–20 mm, and the fine grid used has a mesh size of 2–5 mm.

[0016] In one embodiment, during the primary treatment process, the mixing reaction time of the flocculant is 10–20 minutes; the flocculation and sedimentation time is 40–60 minutes.

[0017] In one embodiment, during the secondary treatment process, the wastewater treated by the activated sludge method is transported to a secondary sedimentation tank for sludge-water separation, wherein the surface loading rate is 0.6–1.2 m³ / (m²×h); and the sedimentation time in the secondary sedimentation tank is 2–4 hours.

[0018] In one embodiment, the method for pre-setting a sliding window for each time moment and determining the influence weight of each type of influencing factor at each time moment based on the discreteness of the correlation between the influencing factors and dissolved oxygen at each time moment within each sliding window is as follows:

[0019] A sliding window is formed by each time point and a preset number of time points preceding it.

[0020] Calculate the correlation coefficients between all element values ​​of each type of environmental factor and all dissolved oxygen within the sliding window at each time point as the correlation coefficients of each type of environmental factor at each time point; calculate the coefficient of variation of the correlation coefficients of each type of influencing factor within the sliding window at each time point.

[0021] The credibility weight of each type of influencing factor is determined based on the coefficient of variation of each type of influencing factor.

[0022] The product of the credibility weight and the correlation coefficient of each type of influencing factor at each time point is used as the influence weight of each type of influencing factor.

[0023] In one embodiment, the confidence weight is positively correlated with the coefficient of variation of each type of influencing factor.

[0024] In one embodiment, the comprehensive influence weight is positively correlated with the time difference and influence weight of all types of influencing factors, and negatively correlated with the fluctuation of the influencing factors.

[0025] In one embodiment, the method for treating wastewater after secondary treatment is as follows:

[0026] The secondary treated wastewater is discharged through an overflow weir and transported to a buffer tank via an outlet pipe; during this process, the wastewater flow rate is 0.5–1.0 m / s; then it is allowed to stand for 15–30 minutes to equalize water quality fluctuations; after standing, it is filtered through a filtration tank.

[0027] Secondly, this application also proposes a comprehensive wastewater filtration and purification system, including a pretreatment module, a primary treatment module, a secondary treatment module, and a tertiary treatment module, to implement the steps of the comprehensive wastewater filtration and purification method.

[0028] Thirdly, embodiments of this application also provide a comprehensive wastewater filtration and purification device, including 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 any of the above-described comprehensive wastewater filtration and purification methods.

[0029] The beneficial effects of this application are as follows:

[0030] In the process of comprehensive wastewater filtration and purification, this application considers that the dissolved oxygen stability in the aeration tank has a significant impact on the decomposition of organic matter by aerobic microorganisms, thus affecting the wastewater treatment effect. Therefore, it analyzes the interference of dissolved oxygen stability. Since fluctuations in temperature and salinity in the aeration tank affect the dissolved oxygen in the wastewater, it is impossible to accurately control the dissolved oxygen in the aeration tank. Temperature and salinity are collected during the treatment process. Considering that increases or decreases in temperature and salinity will inhibit or promote dissolved oxygen to varying degrees, this application analyzes the degree of influence of temperature and salinity fluctuations on dissolved oxygen, obtains the correlation between temperature and salinity and dissolved oxygen under mutual interference, and weights the correlation stability. By combining the comprehensive influence weights with the influence of temperature and salinity on dissolved oxygen, a dynamic scaling factor is constructed to dynamically adjust the fuzzy subset of fuzzy PID control, improving the fine-tuning and convergence speed of fuzzy PID control, and further improving the accuracy of wastewater treatment. Attached Figure Description

[0031] To more clearly illustrate the technical solutions and advantages in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 A flowchart illustrating a comprehensive wastewater filtration and purification method provided in one embodiment of this application;

[0033] Figure 2 This is a flowchart of the control methods in the activated sludge process. Detailed Implementation

[0034] To further illustrate the technical means and effects adopted by this application to achieve the intended purpose of the invention, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a comprehensive wastewater filtration and purification method, equipment, and system proposed in this application. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0036] An embodiment of a comprehensive wastewater filtration and purification method, equipment, and system:

[0037] The following description, in conjunction with the accompanying drawings, details the specific scheme of the comprehensive wastewater filtration and purification method, equipment, and system provided in this application.

[0038] Please see Figure 1 The diagram illustrates a flowchart of a comprehensive wastewater filtration and purification method according to an embodiment of this application, which includes the following steps:

[0039] Step S001: Obtain pretreated wastewater through pretreatment operation.

[0040] First, the wastewater is pretreated.

[0041] Industrial wastewater from factory processing is first filtered through a screen. A coarse screen with a mesh size of 10–20 mm is installed at a 30°–45° angle outside the drain outlet to intercept large floating objects such as tree branches, plastic bottles, and fabrics, protecting downstream equipment from damage. Then, a fine screen with a mesh size of 2–5 mm is installed outside the coarse screen to further filter smaller suspended impurities such as food scraps and hair.

[0042] The filtered wastewater is discharged into a grit chamber for settling for 30-60 seconds to remove heavier inorganic particles (such as sand and slag) and prevent them from abrading pumps and pipes. The settled wastewater is then discharged into an equalization tank where chemicals are added and the wastewater is agitated (mechanical or air) to adjust its pH to 6-8, close to neutral, to meet the requirements of subsequent treatment. The equalization tank balances the wastewater's quality (pH, concentration) and flow rate fluctuations, preventing disruption to subsequent treatment units, thus obtaining pretreated wastewater.

[0043] Preferably, in this embodiment, the mesh size of the coarse screen is 15mm and the mesh size of the fine screen is 3mm; after the wastewater is initially filtered, it is allowed to settle in the sedimentation tank for 60 seconds, and then the pH value of the wastewater is adjusted to 7.

[0044] At this point, the pretreated wastewater was obtained.

[0045] Step S002: Obtain the primary treated wastewater through flocculant sedimentation.

[0046] The pretreated wastewater undergoes primary treatment.

[0047] Pretreated wastewater in the equalization tank is pumped to the sedimentation tank, where flocculants are added to induce flocculation and sedimentation. The optimal dosage of flocculants is determined through laboratory experiments. Water quality is monitored in real time using a pH meter, turbidity meter, and online COD analyzer. The frequency and dosage of the flocculant dosing pump are controlled by PID control. The flocculants are mixed and reacted for 10–20 minutes, followed by sedimentation for 40–60 minutes, thus obtaining the primary treated wastewater.

[0048] Preferably, in this embodiment, the flocculant easing reaction time is 15 minutes and the sedimentation time is 60 minutes.

[0049] Thus, the primary treated wastewater was obtained.

[0050] Step S003: The primary treated wastewater is sent to an aeration tank for treatment using the activated sludge process. The treated mixture is then sent to a secondary sedimentation tank for sludge-water separation to obtain secondary treated wastewater.

[0051] The wastewater after primary treatment is treated by activated sludge process and then separated into sludge and water to obtain secondary treated wastewater.

[0052] The primary treated wastewater from the sedimentation tank is pumped to the aeration tank, where it is mixed with activated sludge returned from the aeration tank and the secondary sedimentation tank. Simultaneously, oxygen is supplied through an aeration device to maintain the dissolved oxygen required for microbial metabolism. Stirring ensures sufficient contact between the sludge and wastewater, thus treating wastewater using the activated sludge process. Sufficient dissolved oxygen is supplied to the aeration tank by an aeration blower or dedicated aerator from the oxygen supply system.

[0053] After activated sludge treatment, the treated mixed liquor is transferred from the aeration tank to the secondary settling tank for sludge-water separation. The surface loading rate is controlled at 0.6–1.2 m³ / (m²×h), and the settling time is 2–4 hours. A scraper is installed in the secondary settling tank to collect the settled sludge into the bottom sludge hopper, while the supernatant is discharged through an overflow weir. A sludge return pump (designed with a return ratio of 50%–100%) returns the sludge from the bottom of the secondary settling tank to the aeration tank, maintaining the sludge concentration in the aeration tank at 3000–5000 mg / L. The remaining sludge is gradually transferred to a thickening tank, where the sludge is held for 12–24 hours for settling. The sludge is then dewatered using a belt filter press, and the treated sludge is incinerated, landfilled, or composted. The supernatant from the secondary settling tank is the secondary treated wastewater.

[0054] The activated sludge process is as follows: Figure 2 As shown.

[0055] S1, the aeration tank is divided into several areas according to distance, and the temperature, salinity and dissolved oxygen of each area are collected at each time.

[0056] In the treatment of primary treated wastewater, dissolved oxygen (DO) content is a key factor in ensuring microbial activity, treatment efficiency, and sludge properties. Maintaining a stable DO content is crucial. However, DO is affected by factors such as temperature and salinity. Therefore, the aeration tank is divided into N equal-interval zones from the inlet to the outlet. An online DO monitor is used at the center of each zone to collect real-time data on temperature, salinity, and DO. The value of N can be adjusted according to the specific circumstances of the implementer; in this embodiment, N is set to 10, and data is acquired every 2 seconds. Historical data from the past week is used for comparative analysis. For each monitoring data point acquired from each zone, Local Outlier Factor (LOF) is used to detect outliers and eliminate their influence.

[0057] This allowed us to obtain the temperature, salinity, and dissolved oxygen at each moment.

[0058] S2 determines the influence weights based on the discreteness of the correlation between temperature, salinity, and dissolved oxygen.

[0059] Typically, wastewater after primary treatment enters the aeration tank through the inlet. Aerobic microorganisms in the aeration tank decompose the organic matter in the wastewater, and the decomposed wastewater flows out from the outlet. During this process, the concentration of organic matter in the wastewater gradually decreases from the inlet to the outlet. Since aerobic microorganisms consume a large amount of dissolved oxygen during the metabolic decomposition of organic matter, areas with higher organic matter content consume more dissolved oxygen, resulting in a gradual increase in dissolved oxygen content from the inlet to the outlet. Therefore, when providing dissolved oxygen for wastewater aeration, a gradual reduction aeration method is commonly used. This method involves a larger air supply at the inlet and a gradual reduction near the outlet, maintaining a dynamic balance between oxygen supply and the oxygen demand of the mixed liquor. The control area for the gradual reduction aeration method is set as N zones divided within the aeration tank, with aeration thresholds set from high to low based on distance from the inlet.

[0060] When oxygen is delivered to wastewater in an aeration tank using a gradual aeration method, the dissolved oxygen content of the wastewater is affected by factors such as temperature and salinity. Aerobic microorganisms in the wastewater consume dissolved oxygen through real-time metabolism, and changes in ambient temperature cause fluctuations in the wastewater temperature. In addition, in a plug-flow aeration tank, as wastewater before the reaction continuously flows in and wastewater after the reaction continuously flows out, the inorganic salt content in the aeration tank also undergoes continuous changes.

[0061] The local temperature and salinity in the aeration tank also change in real time over time. These influencing factors will affect the dissolved oxygen in the local area of ​​the aeration tank when they fluctuate. For each area, a sliding window of length k is constructed by taking each time moment and a preset number of time moments before it. If the number of time moments before each time moment is insufficient, the data is supplemented by filling with the mean.

[0062] Considering that dissolved oxygen is affected by temperature and salinity, both increases in temperature and salinity have an inhibitory effect on dissolved oxygen. However, in reality, the effects of different temperatures and salinities on dissolved oxygen can cancel each other out or accumulate, leading to varying degrees of correlation between temperature and salinity and dissolved oxygen at different times. Therefore, all temperatures within the sliding window corresponding to the current moment are treated as a sequence. Similarly, all salinity and dissolved oxygen within the sliding window corresponding to the current moment are obtained as their respective sequences; these are denoted as temperature sequence, salinity sequence, and dissolved oxygen sequence, respectively. Correlation coefficients are calculated for the temperature and dissolved oxygen sequences, and for salinity and dissolved oxygen sequences at the current moment, to characterize the degree of correlation between temperature and salinity and dissolved oxygen at the current moment. In this embodiment, the correlation coefficients are calculated using the Pearson correlation coefficient.

[0063] If the correlation between an influencing factor and dissolved oxygen fluctuates significantly within a sliding window, the influence of that factor on dissolved oxygen is more unstable, and its current correlation with dissolved oxygen is less reliable. For each sliding window, the correlation coefficients for all times within the sliding window are calculated, and all correlation coefficients between temperature, salinity, and dissolved oxygen are compiled into a sequence as the correlation sequence for each time point.

[0064] The coefficient of variation of all elements in the correlation sequence of temperature and dissolved oxygen is recorded as the first coefficient of variation, and the coefficient of variation of all elements in the correlation sequence of salinity and dissolved oxygen is recorded as the second coefficient of variation. The larger the first and second coefficients of variation are, the greater the fluctuation of the correlation between the two, and the less reliable the correlation analysis is.

[0065] Therefore, the confidence weight of temperature is obtained based on the first coefficient of variation, and the confidence weight of salinity is obtained based on the second coefficient of variation.

[0066] The confidence weight of temperature is positively correlated with the first coefficient of variation, while the confidence weight of salinity is negatively correlated with the second coefficient of variation.

[0067] It should be noted that positive correlation means that when one variable increases, the other variable also increases, and the two variables change in the same direction. When one variable changes from large to small or from small to large, the other variable also changes from large to small or from small to large. The specific relationship is determined by the actual application, and this application does not impose any special restrictions.

[0068] It should be noted that negative correlation means that when one variable increases, the other variable decreases accordingly, and the two variables change in opposite directions. When one variable changes from large to small or from small to large, the other variable also changes from small to large or from large to small. The specific determination is made by practical application, and this application does not impose any special restrictions.

[0069] Preferably, in this embodiment,

[0070] , , This represents the first coefficient of variation. This represents the second coefficient of variation. Represents the normalization function. The confidence weight for temperature is indicated. This represents the confidence weight of salinity.

[0071] Then, the product of the confidence weights of temperature and salinity with the correlation coefficients of temperature and salinity is used as the influence weights of temperature and salinity, respectively.

[0072] Then, the product of the confidence weights of temperature and salinity and the correlation coefficients of temperature and salinity are respectively used as the influence weights of temperature and salinity.

[0073] If temperature and salinity are negatively correlated with dissolved oxygen at the corresponding time, then temperature and salinity will have an inhibitory effect on dissolved oxygen. However, when the reliability of temperature and salinity is high, the correlation between temperature, salinity and dissolved oxygen is relatively stable, and temperature and salinity will show a stable inhibitory effect on dissolved oxygen concentration.

[0074] Thus, the influence weights of temperature and salinity at each moment were obtained.

[0075] S3 determines the comprehensive influence weight based on time differences, influence weights, and fluctuations, and completes the activated sludge process by adjusting the aeration threshold based on this weight.

[0076] Considering that fluctuations in the two influencing factors affect dissolved oxygen levels according to their correlation with dissolved oxygen, and that there may be mutual inhibition or accumulation between the two factors, a comprehensive influence weight is obtained to characterize the combined impact of the two factors on dissolved oxygen. This is based on the time difference between adjacent moments, the fluctuation pattern, and the influence weight of each type of influencing factor.

[0077] The overall influence weight is positively correlated with the time difference and influence weight of all types of influencing factors, and negatively correlated with the fluctuation of influencing factors.

[0078] Preferably, in this embodiment, the expression for the comprehensive influence weight is:

[0079] , This represents the temperature difference between time t and time t-1. This represents the standard deviation of the temperature difference values ​​at all times within the sliding window. This represents the influence weight of the temperature at time t. This represents the salinity difference between time t and time t-1. This represents the standard deviation of the salinity difference across all times within the sliding window. This represents the influence weight of salinity at time t. This represents the overall impact weight at time t. This represents the linear normalization function.

[0080] When temperature shows a negative correlation at time t, and the temperature decreases, then at time t, temperature has a promoting effect on solubility. Similarly, when salinity shows a negative correlation at time t, and salinity fluctuates and decreases, then at time t, salinity also has a promoting effect on solubility. The cumulative combined effect is reflected by summing these effects, and the larger the combined effect weight, the greater the combined effect weight. When both influencing factors show an inhibitory effect, the combined effect increases, and the combined effect weight is larger. Conversely, when one influencing factor inhibits and the other promotes, the combined effect decreases, and the combined effect weight is smaller.

[0081] An initial weight is set, and the sum of the initial weight and the overall influence weight is used as the dynamic scaling factor for command regulation. By characterizing the degree of influence of temperature and salinity on dissolved oxygen, when temperature and salinity fluctuate significantly, the overall influence weight of temperature and salinity increases, requiring a larger mobilization of oxygen supply, and the dynamic scaling factor increases accordingly.

[0082] The dynamic scaling factor can reflect the difference between large fluctuations in temperature and salinity in the same direction and their stable state, and a preset fuzzy subset is used; in this embodiment, the universe of discourse of the initial fuzzy PID control algorithm is... Thus, the fuzzy subset is obtained as The dynamic scaling factor at each moment is multiplied by each element in the fuzzy subset to obtain the real-time adjusted fuzzy subset. This enables dynamic adjustment of the fuzzy subset, allowing for rapid changes in oxygen supply from the aeration equipment through larger control values ​​under severe temperature and salinity variations, while maintaining stability with smaller control values ​​when largely unaffected. The dissolved oxygen setpoints for each region, the current dissolved oxygen level, and the real-time adjusted fuzzy subset are used as inputs to the fuzzy PID control algorithm. The algorithm outputs three control components, which are then sent to the corresponding aeration equipment to adjust the aeration threshold. The fuzzy PID control described is a well-known technique and will not be elaborated upon here.

[0083] After adjusting the aeration threshold, activated sludge treatment is carried out based on this aeration threshold.

[0084] Thus, the wastewater after secondary treatment was obtained.

[0085] Step S004: The wastewater after secondary treatment is allowed to stand in a buffer tank and then filtered to complete the purification of the wastewater.

[0086] The wastewater separated in the secondary sedimentation tank undergoes tertiary treatment. The supernatant from the secondary sedimentation tank is discharged through an overflow weir and transported to a buffer tank via an effluent pipeline. During this process, the flow rate must be controlled at 0.5–1.0 m / s to prevent disturbance of the settled sludge. The solution is retained for 15–30 minutes to balance water quality fluctuations. The settled raw water is then transferred to a V-type filter for deep filtration and purification. The raw water enters the filter evenly through a V-shaped channel, passing through a quartz sand filter layer from top to bottom to intercept suspended solids. The filtered wastewater is then transported from the bottom filter head to a clear water tank, where the equipment is backwashed using the filtered water. This completes the comprehensive wastewater filtration and purification process.

[0087] This completes the filtration and purification of the wastewater.

[0088] Based on the same inventive concept as the above method, embodiments of the present invention also provide a comprehensive wastewater filtration and purification system, including a pretreatment module, a primary treatment module, a secondary treatment module, and a tertiary treatment module; for implementing the steps of the comprehensive wastewater filtration and purification method.

[0089] Based on the same inventive concept as the above methods, embodiments of the present invention also provide a filtration and purification device for comprehensive wastewater, including 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 any one of the above-described methods for filtration and purification of comprehensive wastewater.

[0090] It should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

[0091] 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 comprehensive wastewater filtration and purification method, characterized in that, The method includes the following steps: Industrial wastewater is initially filtered through a screen, and the pre-filtered wastewater is then settled in a grit chamber and the pH value is adjusted to obtain pre-treated wastewater. The pretreated wastewater is transported to a sedimentation tank, where flocculants are added for flocculation and sedimentation. The remaining wastewater after sedimentation is used as the primary treated wastewater. The primary treated wastewater is sent to an aeration tank, where it is treated using the activated sludge process. The treated mixture is then sent to a secondary sedimentation tank for sludge-water separation to obtain secondary treated wastewater. The treatment process using the activated sludge method includes the following steps: S1. Divide the aeration tank into several areas according to distance, and collect the influencing factors and dissolved oxygen in each area at each time. The influencing factors include temperature and salinity. S2, a sliding window is preset for each time point, and the influence weight of each type of influencing factor at each time point is determined based on the discreteness of the correlation between the influencing factors and dissolved oxygen at each time point within each sliding window. S3, based on the time difference between adjacent moments, fluctuations and influence weights of each type of influencing factor, obtain the comprehensive influence weight; after combining the preset initial factor and the comprehensive influence weight, adjust the preset fuzzy subset; use the dissolved oxygen, preset dissolved oxygen setpoint and adjusted fuzzy subset of each region as inputs for fuzzy PID control, and then adjust the preset aeration threshold, and complete the activated sludge process based on the adjusted aeration threshold. The secondary treated wastewater is transported to a buffer tank and allowed to stand. After standing, the wastewater is purified by passing it through a filtration tank. The method for determining the influence weight of each type of influencing factor at each time point based on the discreteness of the correlation between influencing factors and dissolved oxygen at each time point within each sliding window is as follows: A sliding window is formed by each time point and a preset number of time points preceding it. Calculate the correlation coefficients between all element values ​​of each type of environmental factor and all dissolved oxygen within the sliding window at each time point as the correlation coefficients of each type of environmental factor at each time point; calculate the coefficient of variation of the correlation coefficients of each type of influencing factor within the sliding window at each time point. The credibility weight of each type of influencing factor is determined based on the coefficient of variation of each type of influencing factor. The product of the credibility weight and the correlation coefficient of each type of influencing factor at each time point is used as the influence weight of each type of influencing factor. The credibility weight is positively correlated with the coefficient of variation of each type of influencing factor. The comprehensive influence weight is positively correlated with the difference between adjacent time points and the influence weight of all types of influencing factors, and negatively correlated with the fluctuation of the influencing factors.

2. The comprehensive wastewater filtration and purification method as described in claim 1, characterized in that, During the pretreatment process, the coarse grid used has a mesh size of 10–20 mm; the fine grid used has a mesh size of 2–5 mm.

3. The comprehensive wastewater filtration and purification method as described in claim 1, characterized in that, In the primary treatment process, the mixing reaction time of the flocculant is 10-20 minutes; the flocculation and sedimentation time is 40-60 minutes.

4. The comprehensive wastewater filtration and purification method as described in claim 1, characterized in that, In the secondary treatment process, the wastewater treated by the activated sludge method is transported to the secondary sedimentation tank for sludge-water separation, where the surface loading rate is 0.6 to 1.2 m³ / (m²×h); the sedimentation time in the secondary sedimentation tank is 2 to 4 hours.

5. The comprehensive wastewater filtration and purification method as described in claim 1, characterized in that, The method for treating wastewater after secondary treatment is as follows: The secondary treated wastewater is discharged through an overflow weir and transported to a buffer tank via an outlet pipe; during this process, the wastewater flow rate is 0.5–1.0 m / s; then it is allowed to stand for 15–30 minutes to equalize water quality fluctuations; after standing, it is filtered through a filtration tank.

6. A comprehensive wastewater filtration and purification system, comprising a pretreatment module, a primary treatment module, a secondary treatment module, and a tertiary treatment module, characterized in that, Wastewater filtration is performed in different modules using different steps to achieve the steps of a comprehensive wastewater filtration and purification method as described in any one of claims 1-5.

7. A comprehensive wastewater filtration and purification device, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the comprehensive wastewater filtration and purification method as described in any one of claims 1-5.

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