Method for efficiently adding phosphorus removal agent

Abstract

The invention provides a method for efficiently adding a phosphorus removal agent, which comprises the following steps: S1, extracting a water sample in an area to be subjected to phosphorus removal, detecting phosphorus contents in the water samples in different areas, and obtaining an agent adding guide amount according to different phosphorus contents in different water areas; s2, adding polyaluminum chloride according to the determined point location and adding proportion, randomly extracting water samples in different areas after adding, carrying out water test observation, detecting chemical oxygen demand, suspended solids, pH value and total phosphorus content of the water samples after adding the agents according to different proportions, sampling the water quality, and finishing phosphorus removal when the weight of the phosphorus content is less than 0.4 mg / L, otherwise, adding a phosphorus removal agent, and adding a mixed agent of polyaluminum chloride and a phosphorus removal agent. The method has the beneficial effects that the phosphorus in the sedimentation tank is removed in a manner of innovative medicament combination and multi-point addition, the total phosphorus content in the sedimentation tank is removed more efficiently, the cost of the phosphorus removal medicament is reduced, and the phosphorus removal effect is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of phosphorus removal agent dosing, and in particular relates to a method for efficiently dosing a phosphorus removal agent. Background Art

[0002] One of the main methods of phosphorus removal is chemical phosphorus removal. Chemical phosphorus removal agents are mainly divided into four types: aluminum salt phosphorus removal agent, iron salt phosphorus removal agent, calcium salt phosphorus removal agent, and composite phosphorus removal agent. Aluminum salt phosphorus removal agent removes soluble phosphorus by adsorption reaction between metal aluminum ions and phosphate ions; iron salt phosphorus removal agent uses the complex formed by hydrolysis of metal ions to coagulate organic phosphorus and insoluble phosphorus in sewage, and can also directly react and remove; calcium salt phosphorus removal agent mainly removes phosphorus in wastewater by generating calcium-phosphorus precipitates.

[0003] For example, a method and device for adding phosphorus removal agent to a high-efficiency sedimentation tank proposed in 202211112617.3 mainly calculates the dosage of phosphorus removal agent based on the orthophosphate concentration at the outlet of the high-efficiency sedimentation tank, supplemented by feedback adjustment based on the total phosphorus concentration of the effluent from the whole plant and the effluent flow rate from the whole plant, to ensure that the total phosphorus in the effluent meets the discharge standard while saving the consumption of reagents.

[0004] However, when adding phosphorus removal agents, the dosage, location and type of agents are all important indicators. It is particularly important to reasonably choose the location, dosage and type of agents. At the same time, compared with iron salt phosphorus removal agents, polyaluminum chloride phosphorus removal requires excessive dosage to achieve the same effect, but polyaluminum chloride is better than iron salt in removing suspended solids. Therefore, it is necessary to propose an efficient method for adding polyaluminum chloride phosphorus removal agents. Summary of the invention

[0005] In view of this, the present invention aims to provide a method for efficiently adding a phosphorus removal agent to solve at least one technical problem in the background technology.

[0006] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0007] A method for efficiently adding a phosphorus removal agent comprises the following steps:

[0008] S1: Extract water samples from the area to be dephosphorized, test the phosphorus content in water samples from different areas, and derive the guidance amount of the agent according to the different phosphorus content in different waters;

[0009] S2: Add polyaluminium chloride at a determined point and in a certain proportion, randomly draw water samples from different areas for water testing and observation, detect the chemical oxygen demand, suspended solids, pH value and total phosphorus content of the water samples after adding the agent in different proportions, sample the water quality, and complete phosphorus removal when the phosphorus content is less than 0.4mg / L, otherwise proceed to step S3;

[0010] S3: Determine the points and dosage ratios to add the phosphorus removal agent, randomly select water samples from different areas for water testing and observation after adding the agent, detect the chemical oxygen demand, suspended solids, pH value and total phosphorus content of the water samples after adding the agent at different ratios, sample the water quality, and complete the phosphorus removal when the content weight is less than 0.4 mg / L, otherwise proceed to step S4;

[0011] S4: Add a mixture of polyaluminium chloride and phosphorus removal agent. After adding, randomly select water samples from different areas for water testing and observation. Detect the chemical oxygen demand, suspended solids, pH value and total phosphorus content of the water samples after adding the agent in different proportions. Take samples of the water quality. When the content weight is less than 0.4mg / L, phosphorus removal is completed.

[0012] Furthermore, the phosphorus removal agent in step S3 or step S4 includes one or more of an iron salt phosphorus removal agent, a calcium salt phosphorus removal agent, and a composite phosphorus removal agent;

[0013] The phosphorus removal agent in step S3 and the phosphorus removal agent in step S4 may be the same or different.

[0014] Furthermore, the water sample extraction in step S1 is performed by multi-point sampling, and the sampling interval is 50 cm.

[0015] Furthermore, the steps of determining the dosing point in step S1 are specifically as follows:

[0016] A1: Select the sampling points after the water inlet area, in the reaction tank, after the secondary sedimentation tank, and before the water outlet area, take samples and label them;

[0017] A2: Measure the phosphorus content of water samples in different areas separately, and mark the water samples with phosphorus content greater than or equal to 0.4 mg / L;

[0018] A3: Collect water samples with excessive phosphorus content and match them with the sampling area labels, and use the areas with excessive phosphorus content as dosing points.

[0019] Furthermore, the dosage guide amount of the reagent in step S1 is determined according to the phosphorus content of the water sample, and the phosphorus content and the dosage are positively correlated.

[0020] Furthermore, in step S1, the guiding dosage of the agent is obtained according to the different phosphorus contents in different waters:

[0021] In water with a phosphorus content of 0.5-0.8 mg / L, the single-point dosage of liquid polyaluminium chloride is 60 mg / l to 100 mg / l;

[0022] In water with a phosphorus content of 0.8-1 mg / L, the single-point addition amount of liquid polyaluminium chloride is 100 mg / l to 150 mg / l;

[0023] In water with a phosphorus content of 1mg / L-1.5mg / L, the single-point addition amount of liquid polyaluminium chloride is 150mg / l to 300mg / l.

[0024] Furthermore, the measurement of chemical oxygen demand in step S2 includes the following steps: adding potassium dichromate and sulfuric acid, oxidizing the reducing substances in the water sample under heating conditions, and then calculating by titrating the remaining potassium dichromate, and the standard of chemical oxygen demand is 40 mg / L.

[0025] Furthermore, when measuring suspended matter in step S2, the water sample to be tested is placed in a test tube, allowed to settle within a certain period of time, and then the dry weight or wet weight of the sediment is measured to calculate the concentration of the suspended matter, wherein the suspended matter concentration standard is 5 mg / L.

[0026] Furthermore, in step S4, the dosage of polyaluminium chloride is greater than the dosage of other phosphorus removal agents.

[0027] Furthermore, in step S2, the pH value is 6-9, and the chemical oxygen demand, suspended matter, pH value and total phosphorus content are measured 1-2 days after the addition of polyaluminium chloride, and then other phosphorus removal agents are added; in step S3, the chemical oxygen demand, suspended matter, pH value and total phosphorus content are measured 2-3 days after the addition of other phosphorus removal agents, and then mixed addition is performed;

[0028] After 2-3 days of mixing and adding in step S4, chemical oxygen demand, suspended solids, pH value and total phosphorus content are measured.

[0029] Compared with the prior art, the method for efficiently adding a phosphorus removal agent described in the present invention has the following advantages:

[0030] 1. In view of the current situation that the total phosphorus content of the influent is relatively high, the present invention is not limited to the dosage and type of the reagent. The better dosing points are determined through water quality testing, and an innovative combination of reagents and a multi-point dosing method are adopted to remove phosphorus from the sedimentation tank. The total phosphorus content of the sedimentation tank is removed more efficiently, the cost of phosphorus removal reagents is reduced, and the phosphorus removal effect is improved.

[0031] 2. The present invention adopts a mixed addition method of multiple phosphorus removal agents. During the phosphorus removal process in the sedimentation tank, multi-point addition combined with multiple additions is adopted for phosphorus removal. Different types of phosphorus removal agents are added to the same point multiple times. After each agent addition, chemical oxygen demand, suspended solids, pH value and total phosphorus content are tested to determine the best agent to be added, and a subsequent phosphorus removal method is formulated, thereby improving the phosphorus removal quality of the sedimentation tank and improving the subsequent phosphorus removal efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0033] Figure 1 A schematic diagram of a method flow for efficiently adding a phosphorus removal agent according to an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of an embodiment of a method for efficiently adding a phosphorus removal agent according to an embodiment of the present invention. DETAILED DESCRIPTION

[0035] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0036] The specific meanings of the above terms in the present invention should be understood by the specific circumstances.

[0037] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0038] The steps include:

[0039] Step 1: Analyze water quality and determine dosing points

[0040] Take water samples from the area to be dephosphorized at multiple points, test the phosphorus content in water samples from different areas, add polyaluminium chloride to the sampling points, and derive the guiding dosage of the agent according to the different phosphorus content in different waters;

[0041] Step 2: Add polyaluminium chloride

[0042] Polyaluminium chloride is added by determining the points and proportions, and water samples from different areas are randomly drawn for water testing and observation after the addition. The chemical oxygen demand, suspended solids, pH value and total phosphorus content of the water samples after adding the agent at different proportions are detected, and the water quality is sampled. When the content weight is less than 0.4mg / L, phosphorus removal is completed;

[0043] Step 3: Add other phosphorus removal agents

[0044] While implementing the addition of polyaluminium chloride, add the phosphorus removal agent according to the determined points and the amount of agent to be added, detect the chemical oxygen demand, suspended solids, pH value and total phosphorus content of the water sample after adding the agent in different proportions, sample the water quality, and complete the phosphorus removal when the content weight is less than 0.4mg / L;

[0045] Step 4: Implement mixed dosing

[0046] While implementing the addition of polyaluminium chloride and other phosphorus removal agents, the phosphorus removal agent and polyaluminium chloride agent are added separately and mixed. The chemical oxygen demand, suspended solids, pH value and total phosphorus content of the water samples after adding the agents in different proportions are detected. The water quality is sampled, and phosphorus removal is completed when the content weight is less than 0.4mg / L.

[0047] Embodiment 1

[0048] The effluent of Xicheng Wastewater Treatment Plant is currently in compliance with the B standard of DB12 / 599-2015, with the main assessment indicators SS≤5mg / L and TP≤0.4mg / L. These water quality indicators are closely related to the addition of phosphorus removal agents and the reaction system in the deep treatment stage. The scope of the Xicheng Wastewater Treatment Plant in Jinghai New Town, Tianjin includes municipal sewage in an area of ​​about 9.36 square kilometers in Xicheng, Jinghai County. The removal of total phosphorus mainly relies on biochemical pools and the addition of polyaluminum chloride for phosphorus removal. Since the total phosphorus in the influent of Xicheng Wastewater Treatment Plant has been high for a long time, to ensure that the effluent meets the standard, it relies on the addition of PAC at a single point in the mixed reaction for auxiliary phosphorus removal, which consumes more PAC and the treatment effect does not meet expectations. The total phosphorus in the influent is high. It uses a composite phosphorus removal agent, polyaluminum sulfate iron, for phosphorus removal, which has a good phosphorus removal effect and more nitrogen suspended matter. In response to the above problems, after research and discussion, Jinghai Branch decided to combine the phosphorus removal dosing experience of Xicheng and Xiaoyi Water Plants and, based on the treatment status of Xicheng Wastewater Treatment Plant, use multi-point dosing, replacement of agents, and mixed dosing in different proportions as the research content.

[0049] Embodiment 2

[0050] The test was conducted using the on-site conditions in Xicheng, and the test was conducted in different time periods according to the production plan, research plan and test results. PAC agents, phosphorus removal agents and a mixture of the two agents were tried at different proportions at multiple points such as the biochemical pool inlet, biochemical pool outlet and mixed reaction sedimentation tank. The effects of various addition methods were studied and analyzed, the effectiveness of control methods was explored, the operating effects were compared, and continuous optimization was carried out to finally complete the optimized operation plan for multi-point addition of phosphorus removal agents.

[0051] In this embodiment, during the water sample collection stage, water samples are drawn from multiple points in the sedimentation tank with a sampling interval of 50 cm to obtain water samples within a larger range. The water samples are tested and the sample volume is increased to ensure the accuracy of water sample testing.

[0052] In this embodiment, when performing dosing point braking, first select the areas after the water inlet area, in the reaction tank, after the secondary sedimentation tank, and before the water outlet area as sampling points, sample water, and paste labels; then measure the phosphorus content of water samples in different areas respectively, and mark the water samples with a content greater than or equal to 0.4 mg / L; finally, count the water samples marked with excessive phosphorus content, match them with the sampling area labels, and use the areas with excessive phosphorus content as dosing points.

[0053] In this embodiment, the amount of polyaluminium chloride added is determined according to the phosphorus content when the polyaluminium chloride phosphorus removal agent is used. In water with a phosphorus content of 0.5-0.8 mg / L, the single-point addition amount of liquid polyaluminium chloride is 60 mg / l to 100 mg / l; in water with a phosphorus content of 0.8-1 mg / L, the single-point addition amount of liquid polyaluminium chloride is 100 mg / l to 150 mg / l; in water with a phosphorus content of 1 mg / L-1.5 mg / L, the single-point addition amount of liquid polyaluminium chloride is 150 mg / l to 300 mg / l.

[0054] In this embodiment, after the phosphorus removal agent treatment, sampling and testing are carried out, and the testing standards are as follows:

[0055] The standard for chemical oxygen demand is 40 mg / L;

[0056] The suspended matter concentration standard is 5 mg / L;

[0057] pH 6-9.

[0058] In this embodiment, the chemical oxygen demand, suspended solids, pH value and total phosphorus content are measured 1-2 days after the addition of polyaluminium chloride, and then other phosphorus removal agents are added. The chemical oxygen demand, suspended solids, pH value and total phosphorus content are measured 2-3 days after the addition of other phosphorus removal agents, and then mixed addition is carried out. The chemical oxygen demand, suspended solids, pH value and total phosphorus content are measured 2-3 days after the mixed addition.

[0059] In summary, in view of the current situation that the total phosphorus content of the influent is relatively high, the present invention is not limited to the dosage and type of the reagent, and the better dosing points are determined through water quality testing. An innovative combination of reagents and a multi-point dosing method are adopted to remove phosphorus from the sedimentation tank, so as to more efficiently remove the total phosphorus content of the sedimentation tank, reduce the cost of phosphorus removal reagents, and improve the phosphorus removal effect.

[0060] By adopting the above technical scheme, a mixed addition method of multiple phosphorus removal agents is adopted. During the phosphorus removal process in the sedimentation tank, multi-point addition combined with multiple additions is adopted for phosphorus removal. Different types of phosphorus removal agents are added to the same point multiple times. After each agent addition, chemical oxygen demand, suspended solids, pH value and total phosphorus content are tested to determine the best agent to be added, and a subsequent phosphorus removal method is formulated, thereby improving the phosphorus removal quality of the sedimentation tank, and improving the subsequent phosphorus removal efficiency, solving the problem that polyaluminium chloride is better than iron salt in removing suspended solids, but requires excessive addition to achieve the same effect.

[0061] Under the premise of ensuring that the water quality meets the standards, the dosage of the reagents is considered from the perspective of reagent cost: in water with a phosphorus content of 0.5-1 mg / L, polyaluminium chloride is added in a single-point mixed reaction sedimentation tank; in water with a phosphorus content of 1-1.5 mg / L, polyaluminium chloride is added at two points, namely the secondary sedimentation tank and the mixed reaction sedimentation tank; in water with a phosphorus content of >1.5 mg / L, different reagents are added at two points for phosphorus removal, polyaluminium chloride is added in the secondary sedimentation tank, and phosphorus removal agent is added in the mixed reaction sedimentation tank.

[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for efficiently adding a phosphorus removal agent, characterized in that: The steps include: S1: Extract water samples from the area to be dephosphorized, test the phosphorus content in water samples from different areas, and derive the guidance amount of reagent dosage according to the different phosphorus content in different waters; S2: Add polyaluminium chloride at a determined point and in a certain proportion, randomly draw water samples from different areas for water testing and observation, detect the chemical oxygen demand, suspended solids, pH value and total phosphorus content of the water samples after adding the agent in different proportions, sample the water quality, and complete phosphorus removal when the phosphorus content is less than 0.4mg / L, otherwise proceed to step S3; S3: Determine the points and dosage ratios to add the phosphorus removal agent, randomly select water samples from different areas for water testing and observation after adding the agent, detect the chemical oxygen demand, suspended solids, pH value and total phosphorus content of the water samples after adding the agent at different ratios, sample the water quality, and complete the phosphorus removal when the content weight is less than 0.4 mg / L, otherwise proceed to step S4; S4: Add a mixture of polyaluminium chloride and phosphorus removal agent. After adding, randomly select water samples from different areas for water testing and observation. Detect the chemical oxygen demand, suspended solids, pH value and total phosphorus content of the water samples after adding the agent in different proportions. Take samples of the water quality. When the content weight is less than 0.4mg / L, phosphorus removal is completed.

2. The method for efficiently adding a phosphorus removal agent according to claim 1, characterized in that: In step S3 or step S4, the dephosphorization agent includes one or more of an iron salt dephosphorization agent, a calcium salt dephosphorization agent, and a composite dephosphorization agent; The phosphorus removal agent in step S3 and the phosphorus removal agent in step S4 may be the same or different.

3. The method for efficiently adding a phosphorus removal agent according to claim 1, characterized in that: The water samples in step S1 are drawn by multi-point sampling, with a sampling interval of 50 cm.

4. The method for efficiently adding a phosphorus removal agent according to claim 1, characterized in that: The steps for determining the dosing point in step S1 are as follows: A1: Select the sampling points after the water inlet area, in the reaction tank, after the secondary sedimentation tank, and before the water outlet area, take samples and label them; A2: Measure the phosphorus content of water samples in different areas separately, and mark the water samples with phosphorus content greater than or equal to 0.4 mg / L; A3: Collect water samples with excessive phosphorus content and match them with the sampling area labels, and use the areas with excessive phosphorus content as dosing points.

5. The method for efficiently adding a phosphorus removal agent according to claim 1, characterized in that: In step S1, the dosage guide amount of the reagent is determined according to the phosphorus content of the water sample, and the phosphorus content and the dosage are positively correlated.

6. The method for efficiently adding a phosphorus removal agent according to claim 1, characterized in that: In step S1, the dosage guide of the agent is obtained according to the different phosphorus contents in different waters: In water with a phosphorus content of 0.5-0.8 mg / L, the single-point dosage of liquid polyaluminium chloride is 60 mg / l to 100 mg / l; In water with a phosphorus content of 0.8-1 mg / L, the single-point addition amount of liquid polyaluminium chloride is 100 mg / l to 150 mg / l; In water with a phosphorus content of 1mg / L-1.5mg / L, the single-point addition amount of liquid polyaluminium chloride is 150mg / l to 300mg / l.

7. The method for efficiently adding a phosphorus removal agent according to claim 1, characterized in that: The chemical oxygen demand measurement in step S2 includes the following steps: adding potassium dichromate and sulfuric acid, oxidizing the reducing substances in the water sample under heating conditions, and then calculating by titrating the remaining potassium dichromate. The standard of chemical oxygen demand is 40 mg / L.

8. The method for efficiently adding a phosphorus removal agent according to claim 1, characterized in that: When measuring suspended matter in step S2, the water sample to be tested is placed in a test tube and allowed to settle within a certain period of time. The dry weight or wet weight of the sediment is then measured to calculate the concentration of the suspended matter. The standard for the suspended matter concentration is 5 mg / L.

9. The method for efficiently adding a phosphorus removal agent according to claim 1, characterized in that: In step S4, the dosage of polyaluminium chloride is greater than the dosage of other phosphorus removal agents.

10. The method for efficiently adding a phosphorus removal agent according to claim 1, characterized in that: In step S2, the pH value is 6-9, and the chemical oxygen demand, suspended matter, pH value and total phosphorus content are measured 1-2 days after the addition of polyaluminium chloride, and then other phosphorus removal agents are added; 2-3 days after the addition of other phosphorus removal agents in step S3, chemical oxygen demand, suspended solids, pH value and total phosphorus content are measured and then mixed and added; After 2-3 days of mixing and adding in step S4, chemical oxygen demand, suspended solids, pH value and total phosphorus content are measured.

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