Water quality adjusting device for rural domestic sewage treatment

Abstract

The utility model belongs to the technical field of sewage treatment, and relates to a water quality adjusting device for rural domestic sewage treatment, which can effectively stabilize inlet water at an optimal C / N ratio, realizes the adjustment of inlet water concentration through an outlet water backflow mechanism, reduces the risk of biochemical system collapse caused by high load, and improves the water quality. And retreatment of substandard water is realized, and standard discharge of treated water is ensured. The water quality adjusting device comprises a main body, an automatic control system, a water inlet and outlet water quality on-line detection system, a carbon source and PAC adding system, a water outlet three-way control valve and a waste liquid storage barrel, and has the characteristics of high water quality adjusting speed, high automation degree, simplicity and convenience in operation and easiness in maintenance.

Description

Technical Field

[0001] This utility model belongs to the field of wastewater treatment technology, specifically relating to a water quality adjustment method for rural domestic wastewater treatment, and an apparatus for water quality adjustment using this method. Background Technology

[0002] Due to the complex terrain and dispersed population in rural areas, and the small volume and difficulty in collecting sewage in some villages, most villages treat sewage locally using small-scale sewage treatment equipment. This reduces the eutrophication threat to water bodies from pollutants such as nitrogen and phosphorus, solving the problems of high cost and construction difficulty in laying centralized pipe networks, and avoiding the risk of secondary pollution from leaks during sewage transportation. However, rural domestic sewage is characterized by large fluctuations in volume and unstable sewage concentration. Sewage treatment equipment often suffers from deteriorating biochemical reaction conditions due to unstable influent parameters such as COD and TN, making it difficult for some treatment equipment to meet effluent standards.

[0003] In existing wastewater treatment equipment, most influent water quality conditioning technologies, such as carbon source addition and chemical phosphorus removal, rely on manual control, resulting in problems such as response lag and low control precision. Therefore, achieving the desired biochemical reaction conditions through water quality conditioning is not ideal. A small number of influent water quality conditioning technologies employ PID control systems to achieve precise carbon source and reagent addition, significantly improving biochemical reaction conditions. However, because the effluent water quality is not under fully closed-loop control and lacks recirculation and retreatment measures, substandard water is still discharged, failing to achieve the ultimate goal of wastewater treatment. Summary of the Invention

[0004] To address the aforementioned problems, the purpose of this utility model is to provide a water quality adjustment method for rural domestic sewage treatment. This method can effectively stabilize the influent at the optimal biochemical C / N ratio. Through the effluent recirculation mechanism, it not only achieves the adjustment of influent concentration and reduces the risk of biochemical system collapse due to high load, but also enables the re-treatment of substandard water, ensuring that the treated water meets the discharge standards. It features fast water quality adjustment speed, high precision, and good effect.

[0005] Another objective of this invention is to provide a water quality regulation device for rural domestic sewage treatment. This device features a high degree of automation, simple operation, and easy maintenance, effectively achieving water quality regulation and treatment to meet standards.

[0006] A method for water quality regulation in rural domestic sewage treatment, characterized in that it includes an automatic control system, an online influent water quality monitoring system, an online effluent water quality monitoring system, a carbon source dosing system, a PAC dosing system, and an effluent three-way control valve, as well as preset process parameters and operating strategies within the automatic control system;

[0007] The automatic control system collects data from the online influent water quality monitoring system and the online effluent water quality monitoring system. It processes the water quality data through preset process parameters and operating strategies within the automatic control system and uses the results to control the carbon source dosing system, the PAC dosing system, and the effluent three-way control valve.

[0008] The influent water quality online monitoring system samples from the equalization tank and monitors the COD and TN indicators of the influent in real time;

[0009] The online effluent water quality monitoring system samples from the effluent pool and monitors the COD, NH3-N, TN, TP and SS levels in the effluent in real time.

[0010] The carbon source addition system is used for adding carbon sources to the equalization tank;

[0011] The PAC dosing system described above is used for PAC dosing in sedimentation tanks;

[0012] The aforementioned three-way control valve is used to change the direction of water flow and is connected to the water tank, the water outlet, and the lift well respectively. The default state of the three-way control valve is to keep the water tank and the water outlet connected.

[0013] The preset process parameters and operating strategies within the automatic control system include: carbon source dosage algorithm, reflux control strategy for the return water three-way control valve, and PAC dosage algorithm.

[0014] Furthermore, the carbon source dosage algorithm is as follows: Qc_out=Kc_p*e(t)+Kc_i∫e(t)dt+Kc_d*de(t) / dt+α*e(t),

[0015] Where, e(t) = (Qc_in - Qc_set); Qc_out is the calculated value of carbon source dosage; Qc_in is the measured value of carbon source dosage; Qc_set is the set value of carbon source dosage; e(t) is the deviation between the set value and the actual value of carbon source dosage; Kc_p is the proportional gain coefficient for fast deviation response, 0.8 ≤ Kc_p ≤ 3.0; Kc_i is the integral time coefficient for eliminating long-term cumulative errors, 10 ≤ Kc_i ≤ 30; Kc_d is the differential time coefficient for suppressing overshoot and oscillation, 2 ≤ Kc_d ≤ 10; α is the feedforward gain coefficient for compensating for sudden changes, 0.1 ≤ α ≤ 0.2.

[0016] Furthermore, the backflow control strategy of the aforementioned return water three-way control valve is as follows:

[0017] When the COD, NH3-N, TN, TP and SS indicators of the effluent water quality all meet the standards, the effluent three-way control valve does not operate, and the effluent flows from the effluent pool through the effluent three-way control valve to the effluent outlet for direct discharge.

[0018] When one or more of the following indicators of effluent quality—COD, NH3-N, TN, TP, and SS—fail to meet the standards, the effluent flow direction is changed by using the effluent three-way control valve, allowing the substandard effluent to flow back from the effluent pool to the lift well, thereby achieving the re-treatment of the substandard water until the effluent quality meets the discharge standards.

[0019] When one or more of the influent water quality indicators, such as COD and TN, are too high, the outfluent flow direction is changed by using the effluent three-way control valve, allowing the outfluent to flow back from the effluent pool to the lift well, thereby diluting the concentration of the influent, reducing the load on the sewage treatment equipment, until the effluent quality meets the discharge standards.

[0020] Furthermore, the PAC dosage algorithm is as follows: Qp_out = Kp_p*e(t) + Kp_i∫e(t)dt + Kp_d*de(t) / dt.

[0021] Where, e(t) = (Qp_in - Qp_set); Qp_out is the calculated value of PAC dosage; Qp_in is the measured value of PAC dosage; Qp_set is the set value of PAC dosage; e(t) is the deviation between the PAC set value and the actual PAC value; Kp_p is the proportional gain coefficient for fast deviation response, 0.6 ≤ Kp_p ≤ 3.0; Kp_i is the integral time coefficient for eliminating long-term cumulative errors, 10 ≤ Kp_i ≤ 15; Kp_d is the differential time coefficient for suppressing overshoot and oscillation, 2 ≤ Kp_d ≤ 5.

[0022] A water quality regulation device for rural domestic sewage treatment, characterized in that it includes a main body, an automatic control system, an online influent water quality detection system, an online effluent water quality detection system, a carbon source dosing system, a PAC dosing system, an effluent three-way control valve, and a waste liquid storage tank;

[0023] The main body includes an inlet sampling pipe, an outlet sampling pipe, a sampling return pipe, a carbon source dosing pipe, a PAC dosing pipe, an outlet pipe, an outlet discharge pipe that meets standards, and an outlet return pipe;

[0024] The automatic control system uses a touch screen as a human-machine interface to set parameters and display data. It collects data from the online influent water quality detection system and the online effluent water quality detector through the controller, and controls the working status of the carbon source dosing system, PAC dosing system and effluent three-way control valve based on the data processing results.

[0025] The online influent water quality monitoring system includes a COD detector and a TN detector;

[0026] The online effluent water quality monitoring system includes a COD detector, an NH3-N detector, a TN detector, a TP detector, and an SS detector;

[0027] The carbon source dosing system consists of a carbon source metering pump and a carbon source storage tank;

[0028] The PAC dosing system consists of a PAC metering pump and a PAC storage tank;

[0029] The aforementioned outlet three-way control valve is an electric L-type three-way ball valve.

[0030] Furthermore, the aforementioned automatic control system uses a SIMATIC HMI TP1200 Comfort as a touchscreen and a SIMATIC S7-1200 PLC as a controller.

[0031] Furthermore, the aforementioned online influent water quality monitoring system and the online influent water quality monitoring system share a waste liquid storage tank and a sampling return water pipe, with the sampling return water pipe leading to the lift well.

[0032] Compared with the prior art, the beneficial effects of this utility model are:

[0033] This utility model's water quality adjustment method can effectively stabilize the influent at the optimal C / N ratio, providing conditions for biochemical reactions in the wastewater treatment equipment; through the effluent recirculation mechanism, it not only achieves the re-treatment of substandard water, ensuring that the treated water meets discharge standards, but also achieves the adjustment of influent concentration, reducing the risk of biochemical system collapse due to high load;

[0034] This utility model of water quality regulation device features a high degree of automation, simple operation, and easy maintenance, effectively achieving water quality regulation and reliably achieving the standard treatment of sewage. Attached Figure Description

[0035] Figure 1 This is a system diagram of the present invention;

[0036] Figure 2 This is a front view of the main body of this utility model;

[0037] Figure 3 This is a top view of the main body of this utility model;

[0038] Figure 4 This is a left view of the main body of this utility model;

[0039] Figure 5 This is a right view of the main body of this utility model;

[0040] Figure 6 This is a schematic diagram of the operation panel of the automatic control system of this utility model;

[0041] Figure 7 This is a schematic diagram of the internal layout of the automatic control system of this utility model;

[0042] Figure 8This is a schematic diagram of the online influent water quality monitoring system of this utility model;

[0043] Figure 9 This is a schematic diagram of the online effluent water quality monitoring system of this utility model;

[0044] Figure 10 This is a schematic diagram of the carbon source addition system of this utility model;

[0045] Figure 11 This is a schematic diagram of the PAC dosing system of this utility model;

[0046] Figure 12 This is a schematic diagram of the outlet three-way control valve of this utility model;

[0047] Figure 13 Cross-sectional view of the switching path of the outlet three-way control valve of this utility model. Figure 1 ;

[0048] Figure 14 Cross-sectional view of the switching path of the outlet three-way control valve of this utility model. Figure 2 ;

[0049] Figure 15 This is a system diagram of the application object of this utility model;

[0050] Figure 16 This is a general system diagram of an application example of this utility model.

[0051] Figure Labels

[0052] In the diagram: 1. Main body; 2. Automatic control system; 3. Influent water quality online monitoring system; 4. Effluent water quality online monitoring system; 5. Carbon source dosing system; 6. PAC dosing system; 7. Effluent three-way control valve; 8. Waste liquid storage tank; 11. Influent sampling pipe; 12. Effluent sampling pipe; 13. Sampling return pipe; 14. Carbon source dosing pipe; 15. PAC dosing pipe; 16. Effluent pipe; 17. Effluent discharge pipe meeting standards; 18. Effluent return pipe; 21. Touch screen; 22. Controller; 31. Influent COD detector; 32. Influent NH3-N detector; 41. Effluent COD detector; 42. Effluent NH3-N detector; 43. TN detector; 44. TP detector; 45. SS detector; 51. Carbon source metering pump; 52. Carbon source storage tank; 61. PAC metering pump; 62. PAC storage tank. Detailed Implementation

[0053] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0054] Example: Figures 2-14As shown, a water quality adjustment device for rural domestic sewage treatment equipment includes a main body 1, an automatic control system 2, an online influent water quality detection system 3, an online effluent water quality detection system 4, a carbon source dosing system 5, a PAC dosing system 6, an effluent three-way control valve 7, and a waste liquid storage tank 8.

[0055] The main body 1 includes an inlet sampling pipe 11, an outlet sampling pipe 12, a sampling return pipe 13, a carbon source dosing pipe 14, a PAC dosing pipe 15, an outlet pipe 16, an outlet water discharge pipe 17 that meets standards, and an outlet water return pipe 18.

[0056] The automatic control system 2 uses a touch screen 21 as a human-machine interface to set parameters and display data. The controller 22 collects water quality data from the influent water quality online detection system 3 and the effluent water quality online detection system 4, and controls the working status of the carbon source dosing system 5, the PAC dosing system 6 and the effluent three-way control valve 7.

[0057] The online influent water quality monitoring system 3 includes an influent COD detector 31 and an influent TN detector 32;

[0058] The online effluent water quality monitoring system 4 includes an effluent COD detector 41, an effluent NH3-N detector 42, an effluent TN detector 43, an effluent TP detector 44, and an effluent SS detector 45;

[0059] The carbon source dosing system 5 consists of a carbon source metering pump 51 and a carbon source storage tank 52;

[0060] The PAC dosing system 6 consists of a PAC metering pump 61 and a PAC storage tank 62;

[0061] The aforementioned outlet three-way control valve 7 is an electric L-type three-way ball valve.

[0062] Furthermore, the touchscreen 21 is a SIMATIC HMI TP1200 Comfort, and the controller 22 is a SIMATIC S7-1200 PLC.

[0063] Furthermore, the aforementioned online influent water quality monitoring system 3 and online influent water quality monitoring system 4 share a waste liquid storage tank 8 and a sampling return water pipe 13, with the sampling return water pipe 13 leading to the lifting well.

[0064] The instructions for using this utility model are as follows:

[0065] The following will be based on Figure 16 As an application example, the overall system diagram is combined with Figure 1-15The following is an explanation of the use of this utility model. It should be noted that this utility model only provides an auxiliary measure for water quality adjustment of rural domestic sewage treatment equipment, so as to ensure that the influent meets the optimal biochemical reaction conditions, and ensures that the effluent meets the standards before discharge through a reflux mechanism. This utility model cannot replace sewage treatment equipment.

[0066] The influent COD analyzer 31 and the influent TN analyzer 32 sample and analyze water from the equalization tank through the influent sampling pipe 11. The effluent COD detector 41, the effluent NH3-N detector 42, the effluent TN detector 43, the effluent TP detector 44, and the effluent SS detector 45 sample and analyze water from the effluent pool through the effluent sampling pipe 12. The waste liquid generated by the analysis is discharged into the waste liquid storage tank 8, and the sampled water is returned to the lifting well through the sampling return water pipe 13.

[0067] The controller 22 collects influent water quality data from the influent COD analyzer 31 and the influent TN analyzer 32, and controls the operation of the carbon source metering pump 51 based on the calculated carbon source dosage. The carbon source flows into the equalization tank from the carbon source dosing pipe 14. The calculation method for the carbon source dosage is: Qc_out=Kc_p*e(t)+Kc_i∫e(t)dt+Kc_d*de(t) / dt+α*e(t).

[0068] Where, e(t) = (Qc_in - Qc_set); Qc_out is the calculated value of carbon source dosage; Qc_in is the measured value of carbon source dosage; Qc_set is the set value of carbon source dosage; e(t) is the deviation between the set value and the actual value of carbon source dosage; Kc_p is the proportional gain coefficient for fast deviation response, 0.8 ≤ Kc_p ≤ 3.0; Kc_i is the integral time coefficient for eliminating long-term cumulative errors, 10 ≤ Kc_i ≤ 30; Kc_d is the differential time coefficient for suppressing overshoot and oscillation, 2 ≤ Kc_d ≤ 10; α is the feedforward gain coefficient for compensating for sudden changes, 0.1 ≤ α ≤ 0.2.

[0069] The controller 22 collects effluent water quality data from the effluent COD detector 41, effluent NH3-N detector 42, effluent TN detector 43, effluent TP detector 44, and effluent SS detector 45, and performs the following operations:

[0070] When the COD, NH3-N, TN, TP and SS indicators of the effluent water quality all meet the standards, the effluent three-way control valve 7 does not operate, and the effluent flows directly from the effluent pool through the effluent pipe 16 and the effluent qualified discharge pipe 17 for discharge.

[0071] When one or more of the COD and TN indicators of the influent water quality are too high, the outflow direction is changed by the outflow three-way control valve 7, so that the substandard outflow water flows from the outflow pool through the outflow pipe 16 and the outflow return pipe 18 back to the lifting well, thereby diluting the concentration of the influent water, reducing the load on the sewage treatment equipment, until the outflow water quality meets the discharge standards.

[0072] When one or more of the following indicators of effluent quality—COD, NH3-N, TN, TP, and SS—fail to meet the standards, the effluent flow direction is changed by the effluent three-way control valve 7, allowing the substandard effluent to flow from the effluent pool through the effluent pipe 16 and the effluent return pipe 18 back to the lift well, thereby achieving the re-treatment of the substandard water until the effluent quality meets the standards for discharge.

[0073] When the effluent TP quality does not meet the standard, the controller 22 will control the operation of the PAC metering pump 61 according to the automatically calculated PAC dosage. PAC flows into the sedimentation tank from the PAC dosing pipe 15. The algorithm for the PAC dosage is as follows:

[0074] Qp_out=Kp_p*e(t)+Kp_i∫e(t)dt+Kp_d*de(t) / dt,

[0075] Where, e(t) = (Qp_in - Qp_set); Qp_out is the calculated value of PAC dosage; Qp_in is the measured value of PAC dosage; Qp_set is the set value of PAC dosage; e(t) is the deviation between the PAC set value and the actual PAC value; Kp_p is the proportional gain coefficient for fast deviation response, 0.6 ≤ Kp_p ≤ 3.0; Kp_i is the integral time coefficient for eliminating long-term cumulative errors, 10 ≤ Kp_i ≤ 15; Kp_d is the differential time coefficient for suppressing overshoot and oscillation, 2 ≤ Kp_d ≤ 5.

Claims

1. A water quality adjustment device for rural domestic sewage treatment, comprising a main body, an automatic control system, an online influent water quality monitoring system, an online effluent water quality monitoring system, a carbon source dosing system, a PAC dosing system, an effluent three-way control valve, and a waste liquid storage tank, characterized in that: The main body includes an inlet sampling pipe, an outlet sampling pipe, a sampling return pipe, a carbon source dosing pipe, a PAC dosing pipe, an outlet pipe, an outlet discharge pipe that meets standards, and an outlet return pipe; The automatic control system uses a touch screen as a human-machine interface to set parameters and display data. It collects data from the online influent water quality detection system and the online effluent water quality detector through the controller, and controls the carbon source dosing system, PAC dosing system and effluent three-way control valve based on the data processing results. The online influent water quality monitoring system includes a COD detector and a TN detector; The online effluent water quality monitoring system includes a COD detector, an NH3-N detector, a TN detector, a TP detector, and an SS detector; The carbon source dosing system consists of a carbon source metering pump and a carbon source storage tank; The PAC dosing system consists of a PAC metering pump and a PAC storage tank; The aforementioned outlet three-way control valve is an electric L-type three-way ball valve.

2. The water quality conditioning device for rural domestic sewage treatment according to claim 1, characterized in that: The aforementioned automatic control system uses a SIMATIC HMI TP1200 Comfort as the touchscreen and a SIMATIC S7-1200 PLC as the controller.

3. The water quality conditioning device for rural domestic sewage treatment according to claim 1, characterized in that: The aforementioned online influent water quality monitoring system and the online influent water quality monitoring system share a waste liquid storage tank and a sampling return water pipe, with the sampling return water pipe leading to the lift well.

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