High-efficiency phosphorus removal process based on multi-stage precise matching control of phosphate concentration

Abstract

The application belongs to the technical field of sewage treatment, and particularly relates to a high-efficiency phosphorus removal process based on multi-stage precise matching control of phosphate concentration, which comprises the following steps: step S1, the sewage to be treated enters a first-stage coagulation reaction unit from the bottom, coagulation and precipitation reactions occur between the sewage and simultaneously input chemical phosphorus removal reagents in a reaction tank, and then the water is discharged from the top of the reaction tank; step S2, the water is discharged through each coagulation reaction unit, and finally enters a water discharge system from the top of a reaction tank of an Nth-stage coagulation reaction unit, and the phosphorus precipitation enters a sludge discharge system from the bottom of the reaction tank; and step S3, a phosphate real-time monitoring system synchronously and real-timely measures the phosphate concentrations of the water entering each coagulation reaction unit and the total water discharge, and an automatic control system real-timely adjusts the coagulant dosing amount of each coagulation reaction unit. The application can realize precise control of the molar ratio of the phosphorus removal reagent dosing in different phosphate concentration ranges, thereby reducing the overall phosphorus removal reagent dosing amount and realizing fine operation of the sewage treatment process.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to a highly efficient phosphorus removal process based on multi-level precise matching control of phosphate concentration. Background Technology

[0002] Phosphorus, a key factor in eutrophication, needs effective control. 90% of phosphorus in the secondary effluent of urban wastewater treatment plants exists in the form of phosphate, and effective phosphate removal is crucial to ensuring that effluent total phosphorus (TP) meets standards. In the phosphate coagulation and sedimentation removal process, the molar ratio of phosphorus removal agents increases significantly as the phosphate removal target decreases. In actual deep phosphorus removal projects, most rely on excessive dosage of chemical phosphorus removal agents to achieve effective effluent TP control. The problems of large agent dosages and low utilization rates severely restrict the realization of resource utilization goals for urban wastewater treatment effluent in my country. This invention designs a high-efficiency phosphorus removal system based on multi-level precise matching of phosphate concentrations, providing technical support for solving the problem of excessive agent consumption in deep chemical phosphorus removal and offering a new technical direction for deep phosphorus removal in urban wastewater treatment plants. This solution can also be applied to rapid rainwater purification, demonstrating broad development and application potential. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a highly efficient phosphorus removal process based on multi-stage precise matching control of phosphate concentration. This invention addresses the practical problems of low utilization rate and large dosage of chemical phosphorus removal agents in the removal of low-concentration phosphates in traditional deep chemical phosphorus removal processes. Based on the principle that different molar ratios of phosphorus removal agents are required for different phosphate concentrations, this invention develops a highly efficient phosphorus removal process based on multi-stage precise matching control of phosphate concentration. Through multi-stage phosphate removal and precise control of the molar ratio of phosphorus removal agents within different phosphate concentration ranges, the overall dosage of phosphorus removal agents is reduced, achieving low-carbon and refined operation of the wastewater treatment process.

[0004] To achieve the above technical objectives, the technical solution adopted in the embodiments of the present invention is as follows: A highly efficient phosphorus removal process based on multi-level precise matching control of phosphate concentration includes the following steps: Step S1: The wastewater to be treated enters the pipeline mixer of the first-stage coagulation reaction unit of the coagulation reaction system from the inlet system. At the same time, the chemical phosphorus removal agent is added to the pipeline mixer of the first-stage coagulation reaction unit by the dosing system. After mixing, it is transported to the bottom of the reaction tank of the first-stage coagulation reaction unit. Under the action of the stirring system, a coagulation and sedimentation reaction occurs, and then the wastewater is discharged from the top of the reaction tank of the first-stage coagulation reaction unit. Step S2: The effluent passes through the second to Nth stage coagulation reaction units of the coagulation reaction system in sequence, and finally enters the effluent system from the top of the reaction tank of the Nth stage coagulation reaction unit. The phosphorus precipitate generated by each stage coagulation reaction unit enters the sludge discharge system from the bottom of the reaction tank for unified treatment. Step S3: The real-time phosphate monitoring system synchronously and in real-time measures the phosphate concentration in the influent and total effluent of each stage of the coagulation reaction system. The automatic control system receives the phosphate concentration data from the real-time phosphate monitoring system and adjusts the dosage of chemical phosphorus removal agent in each stage of the coagulation reaction unit in real time.

[0005] Furthermore, when the phosphate concentration c1 in the wastewater to be treated in step S1 is greater than 1 mg / L, and the phosphate concentration index requirement of the effluent system in step S2 is c2 < 0.03 mg / L, the coagulation reaction system is composed of five coagulation reaction units connected in series. The molar ratio of chemical phosphorus removal agent added in the first-stage coagulation reaction unit, the second-stage coagulation reaction unit, the third-stage coagulation reaction unit, the fourth-stage coagulation reaction unit, and the fifth-stage coagulation reaction unit is controlled to be 3-4, 5-6, 7-8, 9-10, and 11-15, respectively.

[0006] Furthermore, when the phosphate concentration c1 in the wastewater to be treated in step S1 is greater than 1 mg / L, and the phosphate concentration index of the effluent system in step S2 is required to be 0.03 mg / L ≤ c2 < 0.1 mg / L, the stirring system of the fifth-stage coagulation reaction unit is shut down, and the addition of chemical phosphorus removal agent to the fifth-stage coagulation reaction unit is stopped. At this time, the coagulation reaction system has four stages of coagulation reaction units in operation. The molar ratio of chemical phosphorus removal agent added in the first-stage coagulation reaction unit, the second-stage coagulation reaction unit, the third-stage coagulation reaction unit, and the fourth-stage coagulation reaction unit is controlled to be 3-4, 5-6, 7-8, and 9-10, respectively.

[0007] Furthermore, when the phosphate concentration c1 in the wastewater to be treated in step S1 is greater than 1 mg / L, and the phosphate concentration index of the effluent system in step S2 is required to be 0.1 mg / L ≤ c2 < 0.2 mg / L, the stirring system of the fourth and fifth stage coagulation reaction units is shut down, and the addition of chemical phosphorus removal agents to the fourth and fifth stage coagulation reaction units is stopped. At this time, the coagulation reaction system has three stages of coagulation reaction units in operation. The molar ratio of chemical phosphorus removal agents added in the first, second and third stage coagulation reaction units is controlled to be 3-4, 5-6 and 7-8 respectively.

[0008] Furthermore, when the phosphate concentration in the wastewater to be treated in step S1 is 0.4 mg / L < c1 ≤ 1 mg / L, and the phosphate concentration index of the effluent system in step S2 requires c2 < 0.03 mg / L, the stirring system of the first-stage coagulation reaction unit is shut down, and the addition of chemical phosphorus removal agent to the first-stage coagulation reaction unit is stopped. At this time, the coagulation reaction system has four stages of coagulation reaction units in operation. The molar ratio of chemical phosphorus removal agent added in the second-stage, third-stage, fourth-stage, and fifth-stage coagulation reaction units is controlled to be 5-6, 7-8, 9-10, and 11-15, respectively.

[0009] Furthermore, when the phosphate concentration in the wastewater to be treated in step S1 is 0.2 mg / L < c1 ≤ 0.4 mg / L, and the phosphate concentration requirement of the effluent system in step S2 is c2 < 0.03 mg / L, the stirring system of the first and second stage coagulation reaction units is shut down, and the addition of chemical phosphorus removal agents to the first and second stage coagulation reaction units is stopped. At this time, the coagulation reaction system has three stages of coagulation reaction units in operation. The molar ratio of chemical phosphorus removal agents added in the third, fourth and fifth stage coagulation reaction units is controlled to be 7-8, 9-10 and 11-15 respectively.

[0010] Furthermore, the phosphorus removal process is carried out in a phosphorus removal system, which includes an influent system, a dosing system, a coagulation reaction system, a real-time phosphate monitoring system, an automatic control system, an effluent system, and a sludge removal system. The coagulation reaction system consists of N stages of coagulation reaction units connected in series. The water inlet system is connected to the water inlet of the first stage coagulation reaction unit, and the water outlet system is connected to the water outlet of the Nth stage coagulation reaction unit. Each stage of the coagulation reaction unit includes a pipeline mixer, a stirring system, and a reaction tank. The real-time phosphate monitoring system includes N+1 online phosphate water quality monitoring modules, which are respectively set at the inlet and outlet of each coagulation reaction unit to measure the phosphate concentration at each point in real time. The automatic control system is connected to the phosphate real-time monitoring system, the dosing system, and the stirring system. By receiving and analyzing the phosphate concentration in the influent and effluent of each coagulation reaction unit, it adjusts and precisely controls the dosage of chemicals added to each coagulation reaction unit and the start and stop of the stirring system in real time. Each coagulation reaction unit has a sludge discharge port at the bottom of the reaction tank, which is connected to the sludge discharge system.

[0011] Furthermore, the N-stage coagulation reaction unit has 3≤N≤5, and the hydraulic residence time of each stage coagulation reaction unit is 5min-10min.

[0012] Furthermore, the dosing system is used to quantitatively add chemical phosphorus removal agents to each level of coagulation reaction unit, and to achieve dynamic and differentiated dosing of agents in different coagulation reaction units through an automatic control system.

[0013] The beneficial effects of the technical solution provided by the embodiments of the present invention are as follows: (1) The high-efficiency phosphorus removal system of the present invention is equipped with multi-stage coagulation and sedimentation units to remove phosphate in stages. Based on the automatic control system, the phosphate concentration of the influent and effluent of each stage coagulation and sedimentation unit is monitored in real time. The molar ratio of phosphorus removal agent is precisely matched and controlled for different phosphate removal targets of each stage unit, so as to achieve high-efficiency removal of phosphate.

[0014] (2) The high-efficiency phosphorus removal system of the present invention proposes a precise control scheme for the molar ratio of chemical phosphorus removal agents for different phosphate removal ranges, which can effectively improve the overall agent utilization rate and reduce the agent dosage by more than 20% compared with the traditional single-stage coagulation reaction system.

[0015] (3) The high-efficiency phosphorus removal system of the present invention can flexibly increase the number of coagulation reaction units through an automatic control system to achieve energy saving and consumption reduction during operation, targeting different total influent phosphate concentration and effluent phosphate concentration control targets.

[0016] (4) The high-efficiency phosphorus removal system of the present invention has a wide range of applications. It can be used for chemical phosphorus removal of high-concentration rainwater and sewage, as well as for deep phosphorus removal of low-concentration river and lake water.

[0017] (5) This invention changes the traditional mode of single-temporal sequence for deep chemical phosphorus removal in water plants and develops a new multi-temporal sequence multi-stage phosphorus removal system. It utilizes a real-time phosphate monitoring system and an automatic control system to flexibly adjust the dosage of each reaction unit and the start and stop of the stirring system, thereby achieving efficient phosphorus removal based on the precise matching of phosphorus removal agent molar ratio according to phosphate concentration. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the high-efficiency phosphorus removal system based on multi-level precise matching control of phosphate concentration in an embodiment of the present invention. Detailed Implementation

[0019] A high-efficiency phosphorus removal system based on multi-level precise matching control of phosphate concentration includes an influent system 1, a dosing system 2, a coagulation reaction system 3, a real-time phosphate monitoring system 4, an automatic control system 5, an effluent system 6, and a sludge removal system 7. The coagulation reaction system 3 consists of N coagulation reaction units connected in series, which is the main area for chemical coagulation and phosphorus removal. The inlet system 1 is located at the inlet of the first-stage coagulation reaction unit, and the outlet system 6 is located at the outlet of the Nth-stage coagulation reaction unit, where 3≤N≤5. Each coagulation reaction unit includes a pipe mixer 8, a stirring system 9, and a reaction tank 10. The stirring system 9 consists of a motor and adjustable-speed electrically driven spiral fan blades, which are used to ensure the coagulation reaction of the reagents and the inlet water. The real-time phosphate monitoring system 4 includes N+1 online phosphate water quality monitoring modules, which are respectively set at the inlet and outlet of each coagulation reaction unit to measure the phosphate concentration at each point in real time. The automatic control system 5 is connected to the phosphate real-time monitoring system 4, the dosing system 2 and the stirring system 9. By receiving and analyzing the phosphate concentration in the influent and effluent of each coagulation reaction unit, it adjusts and precisely controls the dosage of chemicals added by the dosing system 2 to each coagulation reaction unit and the start and stop of the stirring system 9 in real time. The bottom of the reaction tank 10 of each coagulation reaction unit has a sludge discharge port, which is connected to the sludge discharge system 7.

[0020] The inlet system 1 is used to introduce the wastewater to be treated into the above-mentioned high-efficiency phosphorus removal system; the outlet system 6 is used to lead the treated water out of the above-mentioned high-efficiency phosphorus removal system; and the sludge discharge system 7 is used to collect coagulation and sedimentation chemical sludge and discharge it periodically.

[0021] The dosing system 2 is used to quantitatively add chemical phosphorus removal agents to each coagulation reaction unit. It can achieve dynamic and differentiated dosing of agents in different coagulation reaction units through the automatic control system 5.

[0022] The hydraulic retention time for each stage of coagulation reaction unit is 5-10 minutes.

[0023] A highly efficient phosphorus removal process based on multi-level precise matching control of phosphate concentration is carried out in the above-mentioned phosphorus removal system, including the following steps: Step S1: The wastewater to be treated enters the pipe mixer 8 of the first-stage coagulation reaction unit of the coagulation reaction system 3 from the inlet system 1. The dosing system 2 simultaneously adds chemical phosphorus removal agent into the pipe mixer 8 of the first-stage coagulation reaction unit. After mixing, the wastewater is transported to the bottom of the reaction tank 10 of the first-stage coagulation reaction unit. Under the action of the stirring system 9, a coagulation and sedimentation reaction occurs, and then the wastewater is discharged from the top of the reaction tank 10 of the first-stage coagulation reaction unit. Step S2: The effluent passes through the second to Nth stage coagulation reaction units of the coagulation reaction system 3 in sequence, and finally enters the effluent system 6 from the top of the reaction tank 10 of the Nth stage coagulation reaction unit. The phosphorus precipitate generated by each stage coagulation reaction unit enters the sludge discharge system 7 from the bottom of the reaction tank 10 for unified treatment. In step S3, the real-time phosphate monitoring system 4 synchronously and in real-time measures the phosphate concentration in the influent and total effluent of each stage of the coagulation reaction system 3. The automatic control system 5 receives the phosphate concentration data from the real-time phosphate monitoring system 4 and adjusts the dosage of chemical phosphorus removal agent in each stage of the coagulation reaction unit in real time.

[0024] When the phosphate concentration c1 in the wastewater to be treated in step S1 is greater than 1 mg / L, and the phosphate concentration requirement of the effluent system 6 in step S2 is c2 < 0.03 mg / L, the coagulation reaction system 3 is composed of five coagulation reaction units connected in series. The molar ratio of chemical phosphorus removal agent added in the first-stage coagulation reaction unit, the second-stage coagulation reaction unit, the third-stage coagulation reaction unit, the fourth-stage coagulation reaction unit and the fifth-stage coagulation reaction unit is controlled to be 3-4, 5-6, 7-8, 9-10 and 11-15 respectively.

[0025] When the phosphate concentration c1 in the wastewater to be treated in step S1 is greater than 1 mg / L, and the phosphate concentration index of the effluent from the effluent system 6 in step S2 is required to be 0.03 mg / L ≤ c2 < 0.1 mg / L, the stirring system 9 of the fifth-stage coagulation reaction unit is shut down, and the addition of chemical phosphorus removal agent to the fifth-stage coagulation reaction unit is stopped. At this time, the coagulation reaction system 3 has four stages of coagulation reaction units in operation. The molar ratio of chemical phosphorus removal agent added in the first-stage coagulation reaction unit, the second-stage coagulation reaction unit, the third-stage coagulation reaction unit, and the fourth-stage coagulation reaction unit is controlled to be 3-4, 5-6, 7-8, and 9-10, respectively.

[0026] When the phosphate concentration c1 in the wastewater to be treated in step S1 is greater than 1 mg / L, and the phosphate concentration index of the effluent from the effluent system 6 in step S2 is required to be 0.1 mg / L ≤ c2 < 0.2 mg / L, the stirring system 9 of the fourth and fifth stage coagulation reaction units is shut down, and the addition of chemical phosphorus removal agents to the fourth and fifth stage coagulation reaction units is stopped. At this time, the coagulation reaction system 3 has three stages of coagulation reaction units in operation. The molar ratio of chemical phosphorus removal agents added in the first, second and third stage coagulation reaction units is controlled to be 3-4, 5-6 and 7-8 respectively.

[0027] When the phosphate concentration in the wastewater to be treated in step S1 is 0.4 mg / L < c1 ≤ 1 mg / L, and the phosphate concentration requirement of the effluent system 6 in step S2 is c2 < 0.03 mg / L, the stirring system 9 of the first-stage coagulation reaction unit is shut down, and the addition of chemical phosphorus removal agent to the first-stage coagulation reaction unit is stopped. At this time, the coagulation reaction system 3 has four stages of coagulation reaction units in operation. The molar ratio of chemical phosphorus removal agent added in the second-stage, third-stage, fourth-stage, and fifth-stage coagulation reaction units is controlled to be 5-6, 7-8, 9-10, and 11-15, respectively.

[0028] When the phosphate concentration in the wastewater to be treated in step S1 is 0.2 mg / L < c1 ≤ 0.4 mg / L, and the phosphate concentration requirement of the effluent system 6 in step S2 is c2 < 0.03 mg / L, the stirring system 9 of the first and second stage coagulation reaction units is shut down, and the addition of chemical phosphorus removal agents to the first and second stage coagulation reaction units is stopped. At this time, the coagulation reaction system 3 has three stages of coagulation reaction units in operation. The molar ratio of chemical phosphorus removal agents added in the third, fourth and fifth stage coagulation reaction units is controlled to be 7-8, 9-10 and 11-15 respectively.

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0030] Example 1 like Figure 1 As shown, a high-efficiency phosphorus removal system based on multi-level precise matching control of phosphate concentration includes an influent system 1, a dosing system 2, a coagulation reaction system 3, a real-time phosphate monitoring system 4, an automatic control system 5, an effluent system 6, and a sludge removal system 7. The coagulation reaction system 3 consists of five coagulation reaction units connected in series, which are the main areas for chemical coagulation and phosphorus removal. They are the first-stage coagulation reaction unit A, the second-stage coagulation reaction unit B, the third-stage coagulation reaction unit C, the fourth-stage coagulation reaction unit D, and the fifth-stage coagulation reaction unit E. Each coagulation reaction unit includes a pipe mixer 8, a stirring system 9, and a reaction tank 10. The water inlet system 1 is connected to the water inlet of the first-stage coagulation reaction unit A, and the water outlet system 6 is connected to the water outlet of the fifth-stage coagulation reaction unit E. The real-time phosphate monitoring system 4 includes 6 online phosphate water quality monitoring modules, which are respectively set at the inlet and outlet of the first-stage coagulation reaction unit A, the second-stage coagulation reaction unit B, the third-stage coagulation reaction unit C, the fourth-stage coagulation reaction unit D and the fifth-stage coagulation reaction unit E, for real-time measurement of phosphate concentration at each point. The automatic control system 5 is connected to the real-time phosphate monitoring system 4, the dosing system 2, and the stirring system 9. By receiving and analyzing the phosphate concentrations in the influent and effluent of each coagulation reaction unit, it adjusts and precisely controls the dosage of chemicals added by the dosing system 2 to each coagulation reaction unit and the start / stop of the stirring system 9 in real time. Each coagulation reaction unit's reaction tank 10 has a sludge discharge port at the bottom, which is connected to the sludge discharge system 7. Based on the target effluent phosphate control value, the automatic control system 5 adjusts the number of coagulation reaction unit stages of the coagulation reaction system 3 by controlling the start / stop of the dosing system 2 and the stirring system 9 in real time.

[0031] The real-time phosphate monitoring system 4 synchronously and in real-time measures the phosphate concentration in the influent and total effluent of each coagulation reaction unit. The automatic control system 5 receives the phosphate concentration data from the real-time phosphate monitoring system 4 and adjusts the dosage of chemical phosphorus removal agent in each coagulation reaction unit in real-time. The molar ratio of chemical phosphorus removal agent in each coagulation reaction unit is controlled sequentially as follows: first-stage coagulation reaction unit A 3-4, second-stage coagulation reaction unit B 5-6, third-stage coagulation reaction unit C 7-8, fourth-stage coagulation reaction unit D 9-10, and fifth-stage coagulation reaction unit E 11-15.

[0032] Example 2 A highly efficient phosphorus removal process based on multi-level precise matching control of phosphate concentration includes the following steps: Step S1: When the influent phosphate concentration is greater than 1 mg / L, and to ensure that the effluent phosphate concentration of the effluent system 6 is less than 0.03 mg / L, the influent system 1 introduces the water to be treated with an influent phosphate concentration greater than 1 mg / L into the pipe mixer 8 of the first-stage coagulation reaction unit A; the dosing system 2 simultaneously adds the chemical phosphorus removal agent into the pipe mixer 8 of the first-stage coagulation reaction unit A; the total influent and the chemical phosphorus removal agent are quickly mixed through the pipe mixer 8 and transported to the bottom of the reaction tank 10 of the first-stage coagulation reaction unit A, where a coagulation and sedimentation reaction occurs under the action of the stirring system 9, with a residence time of 5 minutes, and then the water is discharged from the top of the reaction tank 10 of the first-stage coagulation reaction unit A; Step S2: The effluent passes sequentially through the second-stage coagulation reaction unit B, the third-stage coagulation reaction unit C, the fourth-stage coagulation reaction unit D, and the fifth-stage coagulation reaction unit E, and finally exits from the top of the reaction tank 10 of the fifth-stage coagulation reaction unit E. The sludge generated by coagulation and sedimentation enters the sludge discharge system from the bottom of the reaction tank 10 of each coagulation reaction unit for unified treatment. Step S3: The real-time phosphate monitoring system 4 synchronously and in real-time measures the phosphate concentration in the influent and total effluent of each coagulation reaction unit. The automatic control system 5 receives the phosphate concentration data from the real-time phosphate monitoring system 4 and adjusts the dosage of chemical phosphorus removal agent in each coagulation reaction unit in real-time. The molar ratio of chemical phosphorus removal agent in each coagulation reaction unit is controlled sequentially as follows: first-stage coagulation reaction unit A 3-4, second-stage coagulation reaction unit B 5-6, third-stage coagulation reaction unit C 7-8, fourth-stage coagulation reaction unit D 9-10, and fifth-stage coagulation reaction unit E 11-15.

[0033] Example 3 A highly efficient phosphorus removal process based on multi-level precise matching control of phosphate concentration includes the following steps: Step S1: When the influent phosphate concentration is greater than 1 mg / L, and to ensure that the effluent phosphate concentration of the effluent system 6 is greater than or equal to 0.03 mg / L and less than 0.1 mg / L, the influent system 1 introduces the water to be treated with an influent phosphate concentration greater than 1 mg / L into the pipe mixer 8 of the first-stage coagulation reaction unit A; the dosing system 2 simultaneously adds the chemical phosphorus removal agent into the pipe mixer of the coagulation reaction unit A; the total influent and the chemical phosphorus removal agent are quickly mixed through the pipe mixer 8 and transported to the bottom of the reaction tank 10 of the first-stage coagulation reaction unit A, where a coagulation and sedimentation reaction occurs under the action of the stirring system 9, with a residence time of 5 minutes, and then the water is discharged from the top of the reaction tank 10 of the first-stage coagulation reaction unit A; Step S2: The effluent passes sequentially through the second-stage coagulation reaction unit B, the third-stage coagulation reaction unit C, the fourth-stage coagulation reaction unit D, and the fifth-stage coagulation reaction unit E, following the same process, and finally exits from the top of the reaction tank 10 in the fifth-stage coagulation reaction unit E. No chemical phosphorus removal agents are added to the fifth-stage coagulation reaction unit E, and the stirring system is not activated. The sludge generated from coagulation and sedimentation enters the sludge discharge system from the bottom of the first to fourth-stage coagulation reaction units for final treatment and disposal.

[0034] Step S3: The real-time phosphate monitoring system 4 synchronously and in real-time measures the phosphate concentration in the influent and total effluent of each coagulation reaction unit. The automatic control system 5 receives the phosphate concentration data from the real-time phosphate monitoring system 4 and adjusts the dosage of chemical phosphorus removal agent in each coagulation reaction unit in real-time. The molar ratio of chemical phosphorus removal agent in each coagulation reaction unit is controlled sequentially as follows: first-stage coagulation reaction unit A 3-4, second-stage coagulation reaction unit B 5-6, third-stage coagulation reaction unit C 7-8, and fourth-stage coagulation reaction unit D 9-10.

[0035] Example 4 A highly efficient phosphorus removal process based on multi-level precise matching control of phosphate concentration includes the following steps: Step S1: When the influent phosphate concentration is greater than 0.4 mg / L and less than or equal to 1 mg / L, and to ensure that the effluent phosphate index is less than 0.03 mg / L, the influent system 1 introduces the water to be treated with an influent phosphate concentration greater than 0.4 mg / L and less than or equal to 1 mg / L into the pipe mixer 8 of the first-stage coagulation reaction unit A. No chemical phosphorus removal agent is added to the first-stage coagulation reaction unit A, and the stirring system is not turned on. The water directly flows from the top of the reaction tank 10 of the first-stage coagulation reaction unit A into the second-stage coagulation reaction unit B. The dosing system 2 simultaneously adds the chemical phosphorus removal agent into the pipe mixer 8 of the second-stage coagulation reaction unit B. The total influent and the chemical phosphorus removal agent are quickly mixed through the pipe mixer 8 and transported to the bottom of the reaction tank 10 of the second-stage coagulation reaction unit B. Under the action of the stirring system 9, a coagulation and sedimentation reaction occurs with a residence time of 5 minutes. Then, the water flows out from the top of the reaction tank 10 of the second-stage coagulation reaction unit B. Step S2: The effluent passes through the third-stage coagulation reaction unit C, the fourth-stage coagulation reaction unit D, and the fifth-stage coagulation reaction unit E in the same process, reducing the phosphate concentration to below 0.03 mg / L. The effluent exits from the top of the reaction tank 10 after passing through the fifth-stage coagulation reaction unit E. The sludge generated by coagulation and sedimentation enters the sludge discharge system from the bottom of the second to fifth-stage coagulation reaction units for final treatment and disposal.

[0036] In step S3, the real-time phosphate monitoring system 4 synchronously and in real-time measures the phosphate concentration in the influent and total effluent of each coagulation reaction unit. The automatic control system 5 receives the phosphate concentration data from the real-time phosphate monitoring system 4 and adjusts the dosage of chemical phosphorus removal agent in each coagulation reaction unit in real-time. The molar ratio of chemical phosphorus removal agent in each coagulation reaction unit is controlled sequentially as follows: second-stage coagulation reaction unit B 5-6, third-stage coagulation reaction unit C 7-8, fourth-stage coagulation reaction unit D 9-10, and fifth-stage coagulation reaction unit 11-15.

[0037] Example 5 A highly efficient phosphorus removal process based on multi-level precise matching control of phosphate concentration includes the following steps: Step S1: When the influent phosphate concentration is greater than 0.2 mg / L and less than or equal to 0.4 mg / L, and to ensure that the effluent phosphate index is less than 0.03 mg / L, the influent system 1 introduces the water to be treated with an influent phosphate concentration greater than 0.4 mg / L and less than or equal to 1 mg / L into the pipe mixer 8 of the first-stage coagulation reaction unit A. No chemical phosphorus removal agent is added to the first-stage and second-stage coagulation reaction units A and B, and the stirring system is not turned on. The water directly enters the third-stage coagulation reaction unit C from the top of the reaction tank 10 of the second-stage coagulation reaction unit B. The dosing system 2 simultaneously adds the chemical phosphorus removal agent into the pipe mixer 8 of the third-stage coagulation reaction unit C. The total influent and the chemical phosphorus removal agent are quickly mixed through the pipe mixer 8 and transported to the bottom of the reaction tank 10 of the third-stage coagulation reaction unit C. Under the action of the stirring system 9, a coagulation and sedimentation reaction occurs with a residence time of 5 minutes. Then, the water exits from the top of the reaction tank 10 of the third-stage coagulation reaction unit C. Step S2: The effluent passes through the fourth-stage coagulation reaction unit D and the fifth-stage coagulation reaction unit E in the same process, reducing the phosphate concentration to below 0.03 mg / L. The effluent exits from the top of the reaction tank 10 after passing through the fifth-stage coagulation reaction unit E. The sludge generated by coagulation and sedimentation enters the sludge discharge system from the bottom of the third to fifth-stage coagulation reaction units for final treatment and disposal.

[0038] In step S3, the real-time phosphate monitoring system 4 synchronously and in real-time measures the phosphate concentration in the influent and total effluent of each coagulation reaction unit. The automatic control system 5 receives the phosphate concentration data from the real-time phosphate monitoring system 4 and adjusts the dosage of chemical phosphorus removal agent in each coagulation reaction unit in real-time. The molar ratio of chemical phosphorus removal agent in each coagulation reaction unit is controlled sequentially as follows: C7-8 for the third-stage coagulation reaction unit, D9-10 for the fourth-stage coagulation reaction unit, and 11-15 for the fifth-stage coagulation reaction unit.

[0039] Example 6 A highly efficient phosphorus removal process based on multi-level precise matching control of phosphate concentration includes the following steps: Step S1: When the influent phosphate concentration is greater than 1 mg / L, and to ensure that the effluent phosphate index is greater than 0.1 mg / L and less than or equal to 0.2 mg / L, the influent system 1 introduces the water to be treated with an influent phosphate concentration greater than 1 mg / L into the pipe mixer 8 of the first-stage coagulation reaction unit A; the dosing system 2 simultaneously adds the chemical phosphorus removal agent into the pipe mixer of the coagulation reaction unit A; the total influent and the chemical phosphorus removal agent are quickly mixed through the pipe mixer 8 and transported to the bottom of the reaction tank 10 of the first-stage coagulation reaction unit A, where a coagulation and sedimentation reaction occurs under the action of the stirring system 9, with a residence time of 5 minutes, and then the water is discharged from the top of the reaction tank 10 of the first-stage coagulation reaction unit A; Step S2: The effluent passes sequentially through the second-stage coagulation reaction unit B, the third-stage coagulation reaction unit C, the fourth-stage coagulation reaction unit D, and the fifth-stage coagulation reaction unit E, following the same process, and finally exits from the top of the reaction tank 10 in the fifth-stage coagulation reaction unit E. In the fourth-stage coagulation reaction unit D and the fifth-stage coagulation reaction unit E, no chemical phosphorus removal agents are added, and the stirring system is not activated. The sludge generated from coagulation and sedimentation enters the sludge discharge system from the bottom of the first to third-stage coagulation reaction units for final treatment and disposal.

[0040] In step S3, the real-time phosphate monitoring system 4 synchronously and in real-time measures the phosphate concentration in the influent and total effluent of each coagulation reaction unit. The automatic control system 5 receives the phosphate concentration data from the real-time phosphate monitoring system 4 and adjusts the dosage of chemical phosphorus removal agent in each coagulation reaction unit in real-time. The molar ratio of chemical phosphorus removal agent in each coagulation reaction unit is controlled sequentially as follows: first-stage coagulation reaction unit A 3-4, second-stage coagulation reaction unit B 5-6, and third-stage coagulation reaction unit C 7-8.

[0041] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A highly efficient phosphorus removal process based on multi-level precise matching control of phosphate concentration, characterized in that, Includes the following steps: Step S1: The wastewater to be treated enters the pipe mixer (8) of the first-stage coagulation reaction unit of the coagulation reaction system (3) from the water inlet system (1). The dosing system (2) simultaneously adds the chemical phosphorus removal agent into the pipe mixer (8) of the first-stage coagulation reaction unit. After mixing, the agent is transported to the bottom of the reaction tank (10) of the first-stage coagulation reaction unit. Under the action of the stirring system (9), a coagulation and sedimentation reaction occurs, and then the wastewater is discharged from the top of the reaction tank (10) of the first-stage coagulation reaction unit. Step S2: The effluent passes through the second to Nth stage coagulation reaction units of the coagulation reaction system (3) in sequence, and finally enters the effluent system (6) from the top of the reaction tank (10) of the Nth stage coagulation reaction unit. The phosphorus precipitate generated by each stage coagulation reaction unit enters the sludge discharge system (7) from the bottom of the reaction tank (10) for unified treatment. Step S3: The real-time phosphate monitoring system (4) synchronously and in real-time measures the phosphate concentration of each stage of the coagulation reaction unit in the influent and total effluent of the coagulation reaction system (3). The automatic control system (5) receives the phosphate concentration data from the real-time phosphate monitoring system (4) and adjusts the dosage of chemical phosphorus removal agent in each stage of the coagulation reaction unit in real time. The Nth stage coagulation reaction unit has 3≤N≤5, and the hydraulic retention time of each stage coagulation reaction unit is 5min-10min. The dosing system (2) is used to quantitatively add chemical phosphorus removal agents to each level of coagulation reaction unit, and to realize dynamic differential dosing of agents in different coagulation reaction units through the automatic control system (5); When the phosphate concentration c1 in the wastewater to be treated in step S1 is greater than 1 mg / L, and the phosphate concentration index of the effluent system (6) in step S2 is required to be less than 0.03 mg / L, the coagulation reaction system (3) is composed of five coagulation reaction units connected in series. The molar ratio of chemical phosphorus removal agent added in the first-stage coagulation reaction unit, the second-stage coagulation reaction unit, the third-stage coagulation reaction unit, the fourth-stage coagulation reaction unit and the fifth-stage coagulation reaction unit is controlled to be 3-4, 5-6, 7-8, 9-10 and 11-15 respectively. When the phosphate concentration c1 in the wastewater to be treated in step S1 is greater than 1 mg / L, and the phosphate concentration index of the effluent system (6) in step S2 is required to be 0.03 mg / L ≤ c2 < 0.1 mg / L, the stirring system (9) of the fifth stage coagulation reaction unit is turned off, and the chemical phosphorus removal agent is stopped from being added to the fifth stage coagulation reaction unit. At this time, the coagulation reaction system (3) has four stages of coagulation reaction units in operation. The molar ratio of chemical phosphorus removal agent added in the first stage coagulation reaction unit, the second stage coagulation reaction unit, the third stage coagulation reaction unit and the fourth stage coagulation reaction unit is controlled to be 3-4, 5-6, 7-8 and 9-10 respectively. When the phosphate concentration c1 in the wastewater to be treated in step S1 is greater than 1 mg / L, and the phosphate concentration index of the effluent system (6) in step S2 is required to be 0.1 mg / L ≤ c2 < 0.2 mg / L, the stirring system (9) of the fourth and fifth stage coagulation reaction units is turned off, and the chemical phosphorus removal agent is stopped from being added to the fourth and fifth stage coagulation reaction units. At this time, the three stages of coagulation reaction units in the coagulation reaction system (3) are in operation. The molar ratio of chemical phosphorus removal agent added in the first stage coagulation reaction unit, the second stage coagulation reaction unit and the third stage coagulation reaction unit is controlled to be 3-4, 5-6 and 7-8 respectively. When the phosphate concentration in the wastewater to be treated in step S1 is 0.4 mg / L < c1 ≤ 1 mg / L, and the phosphate concentration index of the effluent system (6) in step S2 requires c2 < 0.03 mg / L, the stirring system (9) of the first-stage coagulation reaction unit is shut down, and the chemical phosphorus removal agent is stopped from being added to the first-stage coagulation reaction unit. At this time, the coagulation reaction system (3) has four stages of coagulation reaction units in operation. The molar ratio of chemical phosphorus removal agent added in the second-stage coagulation reaction unit, the third-stage coagulation reaction unit, the fourth-stage coagulation reaction unit and the fifth-stage coagulation reaction unit is controlled to be 5-6, 7-8, 9-10 and 11-15 respectively. When the phosphate concentration in the wastewater to be treated in step S1 is 0.2 mg / L < c1 ≤ 0.4 mg / L, and the phosphate concentration index of the effluent system (6) in step S2 requires c2 < 0.03 mg / L, the stirring system (9) of the first and second stage coagulation reaction units is shut down, and the chemical phosphorus removal agent is stopped from being added to the first and second stage coagulation reaction units. At this time, the coagulation reaction system (3) has three stages of coagulation reaction units that are still working. The molar ratio of chemical phosphorus removal agent added to the third, fourth and fifth stage coagulation reaction units is controlled to be 7-8, 9-10 and 11-15 respectively.

2. The high-efficiency phosphorus removal process based on multi-level precise matching control of phosphate concentration according to claim 1, characterized in that, The phosphorus removal process is carried out in a phosphorus removal system, which includes an influent system (1), a dosing system (2), a coagulation reaction system (3), a real-time phosphate monitoring system (4), an automatic control system (5), an effluent system (6), and a sludge removal system (7). The coagulation reaction system (3) is composed of N-stage coagulation reaction units connected in series. The water inlet system (1) is located at the water inlet of the first-stage coagulation reaction unit, and the water outlet system (6) is located at the water outlet of the N-stage coagulation reaction unit. Each stage of the coagulation reaction unit includes a pipeline mixer (8), a stirring system (9), and a reaction tank (10). The real-time phosphate monitoring system (4) includes N+1 online phosphate water quality monitoring modules, which are respectively set at the inlet and outlet of each coagulation reaction unit to measure the phosphate concentration at each point in real time. The automatic control system (5) is connected to the phosphate real-time monitoring system (4), the dosing system (2) and the stirring system (9) by receiving and analyzing the phosphate concentration in the influent and effluent of each coagulation reaction unit, and adjusting and precisely controlling the dosage of the dosing system (2) to each coagulation reaction unit and the start and stop of the stirring system (9) in real time; the bottom of the reaction tank (10) of each coagulation reaction unit has a sludge discharge port, which is connected to the sludge discharge system (7).

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