Method for determining coagulant optimal addition quantity and optimal pH in water treatment

A coagulant dosage technology, applied in the field of environmental engineering, can solve the problems of water treatment coagulant dosage and dosage conditions that have not yet been applied, and achieve considerable economic and social benefits, and easy operation

Active Publication Date: 2008-09-17
TIANJIN MUNICIPAL ENG DESIGN & RES INST
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0013] In the actual operation process, the main disadvantage of the coagulation-sedimentation method is to determine an optimal variable each time, but due to the complexity of water quality, it is rarely possible for multiple variables to be optimal at the same time. Dosage, it is necessary to add acid or alkali to the raw water to make several test raw water with different pH, and then conduct different dosage tests on the raw water of each pH. Therefore, in many cases, the results of such tests can only be used as quantitative tests
[0014] The simplex optimization method is a multi-factor optimization method widely used in operations research. It is widely used in analytical testing, experimental design, and data analysis. not yet applied

Method used

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  • Method for determining coagulant optimal addition quantity and optimal pH in water treatment
  • Method for determining coagulant optimal addition quantity and optimal pH in water treatment
  • Method for determining coagulant optimal addition quantity and optimal pH in water treatment

Examples

Experimental program
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Effect test

Embodiment 1

[0056] A method for determining optimum dosage of coagulant and optimum pH in water treatment, comprising the steps of:

[0057] (1) Find the boundary condition of the coagulant dosage, determine the range of the molar ratio of the metal ion in the coagulant to the total phosphorus in the water to be treated:

[0058] The water used in this experiment is the secondary effluent of a sewage treatment plant, and the water quality is shown in Table 1.

[0059] Table 1 Water quality indicators of secondary effluent

[0060] parameter range

[0061] pH 6.80-7.45

[0062] Turbidity (NTU) 2.1-6.0

[0063] Total phosphorus (mg / L) 2.07-4.87

[0064] Orthophosphate (mg / L) 1.21-3.46

[0065] Ammonia nitrogen (mg / L) 26.6-52.3

[0066] Total nitrogen (mg / L) 41.6-113.2

[0067] COD(mg / L) 33.3-65.4

[0068] Take 400mL water samples and place them in six 500mL beakers, add ferric sulfate (see Table 2) to make the Fe / P molar ratio (see Table 2), stir at 200r / min for 1min, and stir at 30...

Embodiment 2

[0103] The coagulant takes aluminum sulfate as an example:

[0104] (1) Find the boundary condition of the coagulant dosage, determine the scope of the molar ratio of the metal ion in the coagulant and the total phosphorus in the water to be treated;

[0105] (2) Find the boundary condition of pH and determine the range of pH value;

[0106](3) Simplex optimization test: (method with reference to Example 1) The boundary conditions determined by experiments are respectively that the dosage Al / P (mol / mol) is between 1-5.0: 1, and the pH value is between 5.0-8.5 between. Choose three points (i.e. points 1, 2, and 3) in this area to start the simplex experiment. When the dosage is 4.13 (Al / P, mol / mol) and the pH value is 6.3, the removal efficiency of aluminum sulfate is the largest , the removal rate of total phosphorus was 95.60% at this time, and the residual concentration of total phosphorus was 0.12mg / L, which reached the standard (GB / T18921-2002) of "Urban Sewage Recycling...

Embodiment 3

[0108] Take the coagulant polyaluminum chloride as an example:

[0109] (1) Find the boundary condition of the coagulant dosage, determine the scope of the molar ratio of the metal ion in the coagulant and the total phosphorus in the water to be treated;

[0110] (2) Find the boundary condition of pH and determine the range of pH value;

[0111] (3) Simplex optimization test: (method with reference to Example 1) The boundary conditions determined by experiments are respectively that the dosage Al / P (mol / mol) is between 1-5.5: 1, and the pH value is between 5.0-8.5 between. Choose three points (namely, points 1, 2, and 3) in this area to start the simplex experiment. When the dosage is 4.37 (Al / P, mol / mol) and the pH value is 5.4, the removal efficiency of polyaluminium chloride is the largest, and the removal rate of total phosphorus is 93.97% at this time, and the residual concentration of total phosphorus is 0.16mg / L, reaching the standard (GB / T18921-2002) of "Urban Sewa...

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Abstract

The invention discloses a method for determining optimal coagulating agent feeding amount and optimal pH value in water treatment, which comprises the following steps of: (1) determining boundary condition of coagulating agent feeding amount, and determining the molar ratio range of metal ions in the coagulating agent and the total phosphorus in the water to be treated; (2) determining boundary condition of pH value and determining the range of pH value; and (3) conducting simplex optimization experiments by collecting a water sample, placing into a container, selecting three points in the molar ratio range of metal ions in the coagulating agent and the total phosphorus in the water sample to be treated, stirring, settling, collecting liquid below liquid level, measuring the concentration of normal phosphate and total phosphorus, and determining the optimal coagulating agent feeding amount and optimal pH value in water treatment according to the result. The inventive method has simple operation and can conveniently determine the optimal coagulating agent feeding amount and optimal pH value in water treatment; and the total phosphorus removal rates using each of the coagulating agents all reach optimal level. The inventive method improves the operational management level of sewage treatment plants and water regeneration plants.

Description

technical field [0001] The invention relates to the field of environmental engineering, in particular to a method for determining the optimum dosage and optimum pH of coagulant in water treatment. Background technique [0002] With the rapid economic development and the acceleration of urbanization, the pollution of my country's urban water environment has intensified, and the problem of water shortage has become more serious. In order to solve this problem, relevant state departments have issued relevant policies one after another. Mainly include: (1) Improve the effluent quality of the sewage treatment plant to the first-class A standard, and reduce the total amount of pollutants discharged into the water environment. (2) Vigorously promote the reuse of sewage. The above two policies both involve controlling the concentration of total phosphorus in the effluent of sewage treatment plants or reclaimed water plants. In order to remove the total phosphorus in the sewage, t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/52
Inventor 王秀朵曹艳芳王玉秋赵乐军韩天玮王洪云
Owner TIANJIN MUNICIPAL ENG DESIGN & RES INST
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