Compound medicament for deep phosphorus removal of domestic sewage as well as preparation method and use method of compound medicament

Abstract

The invention discloses a compound agent for deep phosphorus removal of domestic sewage, a preparation method and a use method, and aims to solve the technical problem that the phosphorus removal effect of a current agent is unsatisfactory, the compound agent comprises polyaluminum ferric chloride and aluminum sulfate according to the ratio of 1%-10%: 90%-99%; the method comprises the step of uniformly mixing polyaluminum ferric chloride and aluminum sulfate, the use method comprises the following steps: (1) adding the compound agent into raw water to be treated in the efficient sedimentation tank of the domestic sewage treatment plant; mixing by using a stirrer; (2) adding a coagulant aid and stirring; (3) standing and precipitating, wherein supernate is treated water; the invention aims to optimize the phosphorus removal performance by scientifically proportioning two main components, namely PAFC (polyaluminum ferric chloride) and aluminum sulfate, overcome the defects in the prior art and realize a more efficient and economical phosphorus removal effect so as to meet the requirements on deep phosphorus removal in current and future domestic sewage treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of environmentally friendly water treatment agents, and in particular to a compound agent for deep phosphorus removal from domestic sewage, a preparation method and a use method thereof. Background Art

[0002] In the field of environmental water treatment technology, phosphorus removal from domestic sewage has always been an important part of the water treatment process. As an important nutrient element, phosphorus, if discharged directly into natural water bodies without effective treatment, will lead to eutrophication of water bodies, seriously affecting water quality ecology and human health. Traditionally, polyaluminum chloride (PAC) single agent has been widely used in the phosphorus removal process in the high-efficiency sedimentation tank process of sewage treatment plants. However, in actual applications, single agents often face problems such as poor phosphorus removal effect, large dosage, and high treatment cost, which makes it difficult to meet increasingly stringent environmental protection standards and energy conservation and emission reduction needs.

[0003] Especially in the field of deep treatment of domestic sewage, the requirements for phosphorus removal efficiency and economy are more urgent. When PAC is used as a single phosphorus removal agent in the traditional way, due to its limited flocculation ability and phosphorus adsorption and precipitation characteristics, it is often necessary to increase the dosage to achieve the expected phosphorus removal effect, which not only increases the treatment cost, but also may bring the risk of secondary pollution. Therefore, it is urgent to independently develop a high-efficiency, low-consumption, low-cost, easy-to-operate composite agent for deep and efficient phosphorus removal of domestic sewage. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art, meet the actual needs, and provide a compound agent, preparation method, and use method for deep phosphorus removal in domestic sewage. The present invention aims to optimize the phosphorus removal performance by scientifically proportioning the two main components of polyaluminium ferric chloride (PAFC) and aluminium sulfate, overcome the shortcomings of the prior art, and achieve a more efficient and economical phosphorus removal effect to meet the current and future needs for deep phosphorus removal in domestic sewage treatment.

[0005] In order to achieve the purpose of the present invention, the technical solution adopted by the present invention is: Disclosed is a compound agent for deep phosphorus removal from domestic sewage, comprising the following components in a weight ratio: polyaluminium ferric chloride: aluminium sulfate = 1%-10%: 90%-99%.

[0006] Polyaluminium ferric chloride:aluminium sulfate=5%:95%.

[0007] The polyaluminium ferric chloride is in solid state, wherein the content of aluminium oxide in the polyaluminium ferric chloride is ≥26%, the content of iron oxide is ≥3%, the basicity is 60%-95%, and the water-insoluble matter is ≤1.0%.

[0008] The polyaluminium ferric chloride is in solid state, and the content of aluminium oxide in the polyaluminium ferric chloride is ≥15.6%, and the content of water insoluble matter is ≤0.2%.

[0009] Furthermore, the present invention also discloses a method for preparing a compound agent for deep phosphorus removal from domestic sewage, the method being used to prepare the compound agent for deep phosphorus removal from domestic sewage as described above, the method comprising: uniformly mixing polyaluminium ferric chloride and aluminium sulfate to obtain the compound agent for deep phosphorus removal from domestic sewage.

[0010] Furthermore, the present invention also discloses a method for using a compound agent for deep phosphorus removal from domestic sewage, wherein the method uses the compound agent as described above and comprises the following steps: (1) adding the compound reagent to the raw water in the high-efficiency sedimentation tank of the domestic sewage treatment plant to be treated; and mixing with a stirrer; (2) Add coagulant and stir; (3) Allow to settle and the supernatant is the treated water.

[0011] In step (1), the compound medicine: raw water = 10mg-30mg: 1 liter; the agitator is stirred at 55rpm for 4 minutes.

[0012] In step (2), the coagulant includes polyacrylamide powder, and the coagulant: raw water = 1 mg: 1 L; stirring is performed slowly at a speed of 20 rpm for 10 minutes.

[0013] In step (3), the mixture is allowed to stand for 60 minutes.

[0014] The beneficial effects of the present invention are: (1) The compound agent of the present invention has a fast chemical reaction speed. The metal ions (such as aluminum ions and iron ions) in PAFC and aluminum sulfate can quickly react with phosphate ions in the water body to form a phosphate precipitate that is insoluble in water, thereby effectively removing phosphorus. The precipitate formed by this compound agent is more stable, has a faster sedimentation rate, and is easy to separate from the water body, thereby improving the phosphorus removal efficiency.

[0015] (2) In addition to removing phosphorus through chemical reactions, PAFC also has good adsorption properties and can effectively adsorb phosphorus in water. The aluminum hydroxide colloid generated by aluminum sulfate can also adsorb suspended matter and some phosphorus in water. After the two are compounded, the adsorption effect is further enhanced, and the alum flowers formed are large and dense, with good precipitation effect, which can effectively improve the phosphorus removal effect.

[0016] (3) PAFC has a fast hydrolysis rate and weak hydration effect, and the iron is high-valent iron, which forms a multi-nuclear complex after hydrolysis. At low temperatures, the alum flowers formed in the water have the characteristics of high specific gravity and compact formation. This is mainly because the hydrolysis rate of iron salts and the hydrolysis process are little affected by temperature. Due to the low iron content, the pH value of the water will not be reduced too much and the chromaticity of the effluent will not be increased. At the same time, aluminum sulfate also shows a significant effect on the purification of micro-polluted, algae-containing, low-temperature and low-turbidity sewage. Therefore, the compound agent of the present invention overcomes the difficulty of water purification of traditional single PAC agents at low temperatures and low turbidity.

[0017] (4) PAFC and aluminum sulfate can both exert good phosphorus removal effects under different pH conditions. Therefore, the compound agent of the present invention can adapt to a wider pH range, thereby having stronger stability and adaptability in practical applications.

[0018] (5) The compound agent of the present invention can maintain long-term stability after being mixed together and placed in a sealed plastic bag due to its reasonable formula and proportion design. For example, when samples were taken out after being stored for half a year and their various flocculation, adsorption and phosphorus removal technical indicators were measured, no significant changes were found compared with the initial samples, proving that it has good stability.

[0019] (6) The compounded agent of the present invention is not only suitable for domestic sewage treatment plants, but can also be used for various industrial wastewater treatment such as chemical industry, printing and dyeing, electroplating, food processing, etc. DETAILED DESCRIPTION

[0020] The present invention is further described below in conjunction with embodiments: Example 1: A compound agent for deep phosphorus removal from domestic sewage, wherein the weight percentages of the various substances in the compound agent are: PAFC (polyaluminium ferric chloride) 1%-10%, aluminium sulfate 90%-99%.

[0021] The PAFC is a commercially available industrial-grade PAFC solid, with an aluminum oxide content of ≥26%, an iron oxide content of ≥3%, a basicity of 60%-95%, and a water-insoluble matter of ≤1.0%.

[0022] The aluminum sulfate is commercially available industrial-grade aluminum sulfate solid, with an aluminum oxide content of ≥15.6% and a water-insoluble matter of ≤0.2%.

[0023] Example 2, a compound agent for deep phosphorus removal from domestic sewage, the weight percentages of the various substances in the compound agent are: PAFC (polyaluminium ferric chloride) 1%, aluminium sulfate 99%.

[0024] The PAFC is a commercially available industrial-grade PAFC solid, with an aluminum oxide content of ≥26%, an iron oxide content of ≥3%, a basicity of 60%-95%, and a water-insoluble matter of ≤1.0%. For example, the aluminum oxide content is 26%, 27%, 28%, 29%, 30% or 31%; the iron oxide content is 3%, 3.3%, 4%, 5%, 6% or 7%; the basicity is 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95%; and the water-insoluble matter is 0.3%, 0.5%, 0.6%, 0.8%, 0.9% or 1.0%.

[0025] The aluminum sulfate is a commercially available industrial-grade aluminum sulfate solid, with an aluminum oxide content of ≥15.6% and a water-insoluble matter of ≤0.2%. For example, the aluminum oxide content is 15.6%, 15.7%, 15.9%, 16.0%, 16.2% or 16.5%; and the water-insoluble matter is 0.2%, 0.18%, 0.16%, 0.14%, 0.12% or 0.10%.

[0026] Example 3, a compound agent for deep phosphorus removal from domestic sewage, the weight percentages of the various substances in the compound agent are: PAFC (polyaluminium ferric chloride) 5%, aluminium sulfate 95%.

[0027] The PAFC is a commercially available industrial-grade PAFC solid, with an aluminum oxide content of ≥26%, an iron oxide content of ≥3%, a basicity of 60%-95%, and a water-insoluble matter of ≤1.0%. For example, the aluminum oxide content is 26%, 27%, 28%, 29%, 30% or 31%; the iron oxide content is 3%, 3.3%, 4%, 5%, 6% or 7%; the basicity is 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95%; and the water-insoluble matter is 0.3%, 0.5%, 0.6%, 0.8%, 0.9% or 1.0%.

[0028] The aluminum sulfate is a commercially available industrial-grade aluminum sulfate solid, with an aluminum oxide content of ≥15.6% and a water-insoluble matter of ≤0.2%. For example, the aluminum oxide content is 15.6%, 15.7%, 15.9%, 16.0%, 16.2% or 16.5%; and the water-insoluble matter is 0.2%, 0.18%, 0.16%, 0.14%, 0.12% or 0.10%.

[0029] Example 4, a compound agent for deep phosphorus removal from domestic sewage, the weight percentages of the substances in the compound agent are: PAFC (polyaluminium ferric chloride) 10%, aluminium sulfate 90%.

[0030] The PAFC is a commercially available industrial-grade PAFC solid, with an aluminum oxide content of ≥26%, an iron oxide content of ≥3%, a basicity of 60%-95%, and a water-insoluble matter of ≤1.0%. For example, the aluminum oxide content is 26%, 27%, 28%, 29%, 30% or 31%; the iron oxide content is 3%, 3.3%, 4%, 5%, 6% or 7%; the basicity is 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95%; and the water-insoluble matter is 0.3%, 0.5%, 0.6%, 0.8%, 0.9% or 1.0%.

[0031] The aluminum sulfate is a commercially available industrial-grade aluminum sulfate solid, with an aluminum oxide content of ≥15.6% and a water-insoluble matter of ≤0.2%. For example, the aluminum oxide content is 15.6%, 15.7%, 15.9%, 16.0%, 16.2% or 16.5%; and the water-insoluble matter is 0.2%, 0.18%, 0.16%, 0.14%, 0.12% or 0.10%.

[0032] Example 5, a compound agent for deep phosphorus removal from domestic sewage, the weight percentages of the substances in the compound agent are: PAFC (polyaluminium ferric chloride) 8%, aluminium sulfate 92%.

[0033] The PAFC is a commercially available industrial-grade PAFC solid, with an aluminum oxide content of ≥26%, an iron oxide content of ≥3%, a basicity of 60%-95%, and a water-insoluble matter of ≤1.0%. For example, the aluminum oxide content is 26%, 27%, 28%, 29%, 30% or 31%; the iron oxide content is 3%, 3.3%, 4%, 5%, 6% or 7%; the basicity is 60%, 65%, 70%, 75%, 80%, 85%, 90% or 95%; and the water-insoluble matter is 0.3%, 0.5%, 0.6%, 0.8%, 0.9% or 1.0%.

[0034] The aluminum sulfate is a commercially available industrial-grade aluminum sulfate solid, with an aluminum oxide content of ≥15.6% and a water-insoluble matter of ≤0.2%. For example, the aluminum oxide content is 15.6%, 15.7%, 15.9%, 16.0%, 16.2% or 16.5%; and the water-insoluble matter is 0.2%, 0.18%, 0.16%, 0.14%, 0.12% or 0.10%.

[0035] Example 6, a method for preparing a compound agent for deep phosphorus removal from domestic sewage. This example is used to prepare a compound agent as described in any one of Examples 1 to 5. The method includes the step of evenly mixing polyaluminum ferric chloride and aluminum sulfate. The compound agent for deep phosphorus removal from domestic sewage is obtained by mixing the above two substances.

[0036] Example 7, a method for using a compound agent for deep phosphorus removal from domestic sewage, the method using the compound agent for deep phosphorus removal from domestic sewage prepared by the method described in Example 6, the method of use is as follows: (1) Add 10 mg to 30 mg of the compound agent for deep phosphorus removal from domestic sewage to 1 liter of the raw water in the high-efficiency sedimentation tank of the domestic sewage treatment plant to be treated, and use a stirrer to quickly mix it at a speed of 55 rpm for 4 minutes; (2) Add the coagulant PAM powder (1 mg / L) and stir slowly at 20 rpm for 10 min; (3) After standing and settling for 60 minutes, the supernatant is the treated water.

[0037] Example 8, a method for using a compound agent for deep phosphorus removal from domestic sewage, the method uses the compound agent for deep phosphorus removal from domestic sewage prepared by the method described in Example 6, and the method of use is as follows: (1) Add 20 mg of the compound agent for deep phosphorus removal from domestic sewage to 1 liter of the raw water in the high-efficiency sedimentation tank of the domestic sewage treatment plant to be treated, and use a stirrer to quickly mix it at a speed of 55 rpm for 4 minutes; (2) Add PAM powder (1 mg / L) and stir slowly at 20 rpm for 10 min; (3) After standing and settling for 60 minutes, the supernatant is the treated water.

[0038] The phosphorus removal effects of the compounded agents in the above examples are compared as follows: Case A: The same agent formula - PAFC 5% and aluminum sulfate 95%, but the dosage is different, as follows: Table 1: Dosage of the drug formula and total phosphorus treatment effect

[0039] Results and conclusion: According to the above experimental data, the optimal dosage of the compound agent is 20 mg / L. The total phosphorus content of the raw water in the high-efficiency sedimentation tank after treatment is low, which has reached the first-level A effluent standard of the pollutant discharge standard for urban sewage treatment plants (GB18918-2002) (total phosphorus <0.5 mg / L), and is better than the phosphorus removal effect of the sewage plant using the traditional PAC single agent (control group) with a dosage of 30 mg / L. Therefore, the use of the compound agent reduces the dosage of the agent by 33%.

[0040] Case B: The dosage of the same compound agent is 20 mg / L, but the formulations of the components are different, as follows: Table 2: Dosage of the drug formula and total phosphorus treatment effect

[0041] Results and conclusion: According to the above experimental data, when the compound ratio of the compound agent is PAFC5% and aluminum sulfate 95%, the total phosphorus content of the raw water after treatment in the high-efficiency sedimentation tank is the lowest, the phosphorus removal effect is the best, and it meets the Class A effluent standard of the Pollutant Discharge Standard for Urban Wastewater Treatment Plants (GB18918-2002) (total phosphorus <0.5 mg / L), which is more than 2 times higher than that of other single agents (control group).

[0042] The embodiments of the present invention disclose preferred embodiments, but are not limited thereto. A person skilled in the art can easily understand the spirit of the present invention based on the above embodiments and make different extensions and changes. However, as long as they do not deviate from the spirit of the present invention, they are all within the protection scope of the present invention.

Claims

1. A compound agent for deep phosphorus removal from domestic sewage, characterized in that: It includes the following components in weight ratio: polyaluminium ferric chloride: aluminium sulfate = 1% - 10%: 90% - 99%.

2. The compound agent for deep phosphorus removal from domestic sewage according to claim 1, characterized in that: Polyaluminium ferric chloride:aluminium sulfate=5%:95%.

3. The composite agent for deep phosphorus removal from domestic sewage according to claim 1, characterized in that: The polyaluminium ferric chloride is in solid state, wherein the content of aluminium oxide in the polyaluminium ferric chloride is ≥26%, the content of iron oxide is ≥3%, the basicity is 60%-95%, and the water-insoluble matter is ≤1.0%.

4. The compound agent for deep phosphorus removal from domestic sewage according to claim 1, characterized in that: The polyaluminium ferric chloride is in solid state, and the content of aluminium oxide in the polyaluminium ferric chloride is ≥15.6%, and the content of water insoluble matter is ≤0.2%.

5. A method for preparing a compound agent for deep phosphorus removal from domestic sewage, characterized in that: The method is used to prepare the compound agent for deep phosphorus removal from domestic sewage as claimed in any one of claims 1 to 4, and the method comprises: uniformly mixing polyaluminium ferric chloride and aluminium sulfate to obtain the compound agent for deep phosphorus removal from domestic sewage.

6. A method for using a compound agent for deep phosphorus removal from domestic sewage, characterized in that: Using the compound agent for deep phosphorus removal from domestic sewage as described in claims 1-4 comprises the following steps: (1) adding the compound reagent to the raw water in the high-efficiency sedimentation tank of the domestic sewage treatment plant to be treated; and mixing with a stirrer; (2) Add coagulant and stir; (3) Allow to settle and the supernatant is the treated water.

7. The method for using the compound agent for deep phosphorus removal from domestic sewage according to claim 6, characterized in that: In step (1), the compound medicine: raw water = 10mg-30mg: 1 liter; the agitator is stirred at 55rpm for 4 minutes.

8. The method for using the compound agent for deep phosphorus removal from domestic sewage according to claim 6, characterized in that: In step (2), the coagulant includes polyacrylamide powder, and the coagulant: raw water = 1 mg: 1 L; stirring is performed slowly at a speed of 20 rpm for 10 minutes.

9. The method for using the compound agent for deep phosphorus removal from domestic sewage according to claim 6, characterized in that: In step (3), the mixture is allowed to stand for 60 minutes.

Images