Treatment method for efficiently removing hardness by using high-salinity wastewater

Abstract

The invention discloses a treatment method for efficiently removing hardness by using high-salinity wastewater. The treatment method comprises the following steps: introducing the high-salinity wastewater into an adjusting tank, and stirring and mixing; adding alkali liquor into the mixed water in the adjusting tank to generate insoluble precipitates so as to remove the hardness in the water; introducing the softened wastewater into a sedimentation tank, and further promoting the aggregation and sedimentation of suspended solids and sediments by adding a flocculating agent; inputting supernatant after flocculation and precipitation into filter pressing equipment for filtering to obtain filtrate and filter residues; according to the process scheme designed by the invention, the sulfate-containing wastewater is added into the water treatment regulating tank, so that the content of calcium and magnesium in the wastewater can be effectively reduced, the hardness is reduced, and the purposes of treating waste with waste and turning waste into wealth are really achieved.

Description

Technical Field

[0001] The invention relates to the technical field of water treatment, and in particular to a treatment method for efficiently removing hardness from high-salinity wastewater. Background Art

[0002] In water treatment plants, a large amount of sludge is accumulated in regulating pools after long-term use, resulting in a reduction in water storage capacity. In addition, there is also the problem of extremely high hardness of raw water in some regulating pools, which has a great impact on the subsequent use of trisodium phosphate reagents;

[0003] In order to solve these problems, we proposed a waste utilization method, using high-salt wastewater containing sulfate to treat the hardness of raw water in the regulating tank. After filtration, the filtrate obtained can be used in subsequent water treatment processes. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a method for efficiently removing hardness from high-salinity wastewater.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for efficiently removing hardness from high-salinity wastewater comprises the following steps:

[0007] S1. Pretreatment: The high-salt wastewater is introduced into the regulating tank and stirred and mixed, and the water quality and water quantity are balanced through the regulating tank;

[0008] S2, softening treatment: adding alkali solution to the mixed regulating pool water to generate insoluble precipitate to remove the hardness in the water;

[0009] S3, flocculation sedimentation: The softened wastewater is introduced into the sedimentation tank, and flocculants are added to further promote the aggregation and sedimentation of suspended matter and sediment;

[0010] S4, filter pressing: the supernatant after flocculation precipitation is input into the filter pressing equipment for filtration to obtain filtrate and filter residue;

[0011] S5. The filtrate after filtration is transported to a storage tank for storage, and then transported to a water treatment workshop for further purification.

[0012] Preferably, a submersible mixer is provided in the regulating tank for stirring and mixing water.

[0013] Preferably, the alkaline solution in step S2 includes sodium carbonate solution and magnesium chloride solution, which react with the regulating pool water to generate insoluble magnesium hydroxide and calcium carbonate precipitates.

[0014] Preferably, the compression equipment used in step S4 is a plate and frame filter press or a belt filter press.

[0015] Preferably, the filter residue produced by the filter pressing in step S4 is disposed of by landfill.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] In the present invention, high-salt wastewater containing sulfate is used to treat the hardness of raw water in the regulating tank. After filter pressing, the filtrate obtained can be used in subsequent water treatment processes;

[0018] Adding sulfate-containing wastewater to the water treatment regulating tank can effectively reduce the calcium and magnesium content in the wastewater, thereby reducing the hardness, truly achieving the goal of treating waste with waste and turning waste into treasure;

[0019] The process flow designed by the present invention treats waste with waste, relies on existing water treatment stations, has low project investment, is convenient to operate, easy to manage, and has no secondary pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more specifically and intuitively illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below.

[0021] Figure 1 The present invention provides a flow chart of a method for efficiently removing hardness from high-salinity wastewater. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0023] Reference Figure 1 A method for efficiently removing hardness from high-salinity wastewater comprises the following steps:

[0024] S1. Pretreatment: The high-salt wastewater is introduced into the regulating tank and stirred and mixed, and the water quality and water quantity are balanced through the regulating tank;

[0025] The regulating tank is used to homogenize high-salinity wastewater to ensure the stability of the water quality of the subsequent treatment units, thereby ensuring the continuous and stable operation of the entire treatment system;

[0026] In the hardness removal scheme using high-salt wastewater mixed with raw water from the regulating pond, without adding alkali solution, the raw water contains Ca 2+ When the hardness removal rate can reach 70%, the reaction principle is as follows:

[0027] Ca 2+ +SO4 2-+H2O=CaSO4·2H2O↓;

[0028] S2, softening treatment: adding alkali solution to the mixed regulating pool water to generate insoluble precipitate to remove the hardness in the water;

[0029] According to the specific composition and treatment objectives of the wastewater, sodium carbonate solution is slowly added to the water to gradually increase the pH value. As an alkaline substance, sodium carbonate can neutralize the acidic components in the wastewater, such as sulfate ions, thereby reducing the acidity of the wastewater;

[0030] S3, flocculation sedimentation: The softened wastewater is introduced into the sedimentation tank, and flocculants are added to further promote the aggregation and sedimentation of suspended matter and sediment;

[0031] S4, filter pressing: the supernatant after flocculation precipitation is input into the filter pressing equipment for filtration to obtain filtrate and filter residue;

[0032] S5. The filtrate after filtration is transported to a storage tank for storage, and then transported to a water treatment workshop for further purification.

[0033] A submersible mixer is installed in the regulating tank for stirring and mixing water treatment.

[0034] In step S2, the alkali solution includes a sodium carbonate solution and a magnesium chloride solution, which react with the regulating pool water to generate insoluble magnesium hydroxide and calcium carbonate precipitates;

[0035] In the process of adding sodium carbonate, the wastewater in the regulating tank needs to be stirred continuously to promote the uniformity of the chemical reaction. The stirring speed and time should be determined according to the volume of the wastewater and the pH range to be adjusted. Sodium carbonate needs to be added slowly. If the sodium carbonate is added too quickly, it will quickly react with the sulfate in the wastewater to form sodium bicarbonate and water. This process will be accompanied by the generation of a large number of carbon dioxide bubbles, which not only makes it difficult to accurately control the final pH value, but may also cause splashing and overflow, increasing the difficulty of operation and safety risks;

[0036] The effect of magnesium chloride solution is that under alkaline conditions, calcium sulfate precipitate is generated and a small amount of magnesium hydroxide colloid exists. The presence of magnesium hydroxide colloid can accelerate the precipitation of calcium sulfate. At the same time, the precipitate has a huge surface area and can adsorb and wrap substances such as iron hydroxide and silicon dioxide. During the precipitation process, part of SO42-, Mn2+ ions can be removed through synergistic precipitation to achieve further purification.

[0037] The compression equipment used in step S4 is a plate and frame filter press or a belt filter press.

[0038] The filter residue produced by the filter pressing in step S4 is disposed of by landfill.

[0039] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for efficiently removing hardness from high-salinity wastewater. It is characterized in that The following steps are involved: S1. Pretreatment: The high-salt wastewater is introduced into the regulating tank and stirred and mixed, and the water quality and water quantity are balanced through the regulating tank; S2, softening treatment: adding alkali solution to the mixed regulating pool water to generate insoluble precipitate to remove the hardness in the water; S3, flocculation sedimentation: The softened wastewater is introduced into the sedimentation tank, and flocculants are added to further promote the aggregation and sedimentation of suspended matter and sediment; S4, filter pressing: the supernatant after flocculation precipitation is input into the filter pressing equipment for filtration to obtain filtrate and filter residue; S5. The filtrate after filtration is transported to a storage tank for storage, and then transported to a water treatment workshop for further purification.

2. A method for efficiently removing hardness from high-salinity wastewater according to claim 1, It is characterized in that The regulating tank is provided with a submersible mixer for water treatment, stirring and mixing.

3. A method for efficiently removing hardness from high-salinity wastewater according to claim 1, It is characterized in that The alkaline solution in step S2 includes sodium carbonate solution and magnesium chloride solution, which react with the regulating pool water to generate insoluble magnesium hydroxide and calcium carbonate precipitates.

4. A method for efficiently removing hardness from high-salinity wastewater according to claim 1, It is characterized in that The compression equipment used in step S4 is a plate and frame filter press or a belt filter press.

5. A method for efficiently removing hardness from high-salinity wastewater according to claim 1, It is characterized in that The filter residue produced by the filter pressing in step S4 is disposed of by landfill.

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