A sludge deep conditioning agent composition and a method for deeply dewatering sludge using the composition

Abstract

The present invention belongs to the technical field of sewage treatment, and specifically provides a sludge deep conditioner composition and a method for deeply dewatering sludge by using the composition. By using a cell wall breaker, a protein astringent, and a modified tannin flocculant as raw materials and carrying out appropriate weight ratios, the finally prepared sludge deep conditioner composition can fully release the internal and external moisture of the sludge and improve the dehydration efficiency. The sludge conditioner composition of the present invention has a high degree of designability. During the conditioning process of excess sludge, the dosage of the agent is small and the dehydration effect is good. The molecular chain of the sludge deep conditioner composition of the present invention has a high density of cationic charges and strong electro-neutralization adsorption ability, and has a good flocculation effect, and can be applied to the conditioning of excess sludge.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewage treatment, and particularly relates to a sludge deep conditioning agent composition and a method for deeply dehydrating sludge by using the composition. Background Art

[0002] As the final product of water treatment, sludge has problems such as high water content and difficult dehydration. The moisture content of the excess sludge generated by municipal sewage treatment plants is generally between 95% and 99%, and the volume is huge. Therefore, sludge reduction first requires sludge volume reduction, and dehydration reduction is an important link to reduce the subsequent treatment cost of sludge and improve the sludge treatment efficiency. Due to the characteristics of high organic matter content, fine particles, strong hydrophilicity, and strong colloidal structure in sludge, sludge dehydration is difficult. The water contained in sludge can be roughly divided into free water, capillary water, bound water, and intracellular water. Among them, free water accounts for about 70% of the total water, capillary water accounts for about 20% of the total water, and bound water and intracellular water account for about 10% of the total water. Free water can be easily removed by concentration or applying a very small mechanical force, while capillary water and bound water need to be treated by adding strong chemical agents and other methods before they can be removed, and intracellular water must pass through cell wall breaking before it can be released.

[0003] The key to using a flocculant to condition sludge lies in the selection of the flocculant. At present, the flocculants used in water treatment are mainly divided into two categories: inorganic flocculants and organic flocculants. Inorganic flocculants are mainly polyaluminum and polyferric flocculants, which have good coagulation effects, wide application ranges, strong electro-neutralization abilities, and low unit prices. However, they also have many problems such as large dosages, toxic residual metals, certain corrosion to pipeline equipment, and affecting the subsequent resource utilization of sludge. There are many types of organic polymer flocculants, usually with less dosage, fast floc formation speed, and very excellent adsorption bridging ability. However, their electro-neutralization ability is weak, and their ability to remove organic matter is poor. Especially in the conditioning and dehydration of excess sludge, they cannot reach the level of deep treatment.

[0004] Therefore, how to obtain a sludge deep conditioning agent with good cell wall breaking effect, good flocculation performance, and high floc density by reasonably selecting raw materials, improving the preparation method and dosing method is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] To solve the above problems existing in the prior art, the present invention provides a sludge deep conditioner composition and a method for deeply dewatering sludge using this composition. The sludge deep conditioner composition of the present invention has a high degree of designability. During the conditioning process of excess sludge, the dosage of the agent is small and the dewatering effect is good. The molecular chain of the sludge deep conditioner composition of the present invention has a high density of cationic charges and strong electro-neutralization adsorption ability, and has a good flocculation effect, and can be applied to the conditioning of excess sludge. The method of the present invention can fully release the internal and external moisture of the sludge and improve the dewatering efficiency.

[0006] The technical solution adopted by the present invention is as follows:

[0007] The first aspect of the present invention provides a sludge deep conditioner composition, and the raw material components include:

[0008] Cell wall breaker, 5 - 20 parts by weight;

[0009] Protein coagulant, 20 - 60 parts by weight;

[0010] Modified tannin flocculant, 20 - 60 parts by weight.

[0011] Preferably, the cell wall breaker is any one or more of potassium ferrate, potassium permanganate, and sodium percarbonate.

[0012] Preferably, the protein coagulant is any one or more of aluminum sulfate, zinc carbonate, and sodium humate.

[0013] Preferably, the modified tannin flocculant is a product copolymerized from tannin, dimethyldiallylammonium chloride, and N,N - methylenebisacrylamide.

[0014] The second aspect of the present invention provides a preparation method of the modified tannin flocculant, which is specifically as follows:

[0015] (a) By mass, add 2 - 8 parts of tannin, 200 - 600 parts of dimethyldiallylammonium chloride, 1 - 3 parts of N,N - methylenebisacrylamide, and 130 - 400 parts of distilled water to obtain a monomer solution;

[0016] Add 0.1 - 0.5 part of chelating agent to the monomer solution, and carry out sufficient mixing and dissolution under stirring conditions, and deoxygenate by passing nitrogen;

[0017] (b) By mass, slowly add 0.03 - 0.5 part of initiator to the solution system obtained in step (a), initiate polymerization, and after the system temperature rises to 50 - 60 °C, keep warm for 2 - 6 h to obtain an aqueous solution of the modified tannin flocculant.

[0018] Preferably, in step (a), the dimethyldiallylammonium chloride is an aqueous solution of dimethyldiallylammonium chloride with a mass percentage content of 60% - 65%.

[0019] Preferably, in step (a), in the monomer solution, the total solid content of tannin, dimethyldiallylammonium chloride, and N,N - methylenebisacrylamide is 35 wt% - 45 wt%.

[0020] Preferably, in step (a), the chelating agent is a mixture composed of disodium ethylenediaminetetraacetate and diethylenetriamine pentamethylenephosphonic acid in a mass ratio of 2:(1 - 3);

[0021] The initiator is any one or more of potassium persulfate, ammonium persulfate, ammonium cerium nitrate, and azobisisobutyramidine hydrochloride;

[0022] The viscosity of the aqueous solution of the modified tannin flocculant is above 100,000 cps, and the solid content concentration is 40%. The third aspect of the present invention provides a method for deeply dewatering sludge using the sludge deep conditioning agent composition, including the following steps:

[0023] S1. Add the cell wall breaker to the sludge to be treated and stir until fully mixed; the dosage of the cell wall breaker is 0.5% - 1% of the dry weight of the sludge;

[0024] S2. Add the protein astringent to the sludge treated in step (S1) and stir until fully mixed; the dosage of the protein astringent is 1% - 5% of the dry weight of the sludge;

[0025] S3. Add the modified tannin flocculant to the sludge treated in step (S2) and stir until fully mixed; the dosage of the modified tannin flocculant is 1% - 5% of the dry weight of the sludge; It should be noted that the actually added is the aqueous solution of the modified tannin flocculant, but the dosage of 1% - 5% is calculated according to the solid phase addition amount of the modified tannin flocculant;

[0026] S4. Let the sludge treated in step (S3) stand in the conditioning tank for 10 - 15 min, and then perform pressure filtration dehydration, that is, complete the deep dehydration of the sludge.

[0027] Preferably, the specific operating conditions for the pressure filtration dehydration are: perform pressure filtration treatment at a pressure of 0.8 - 1.5 MPa for 30 - 40 min, and the pressure filtration is completed;

[0028] The filter press is a plate - and - frame filter press;

[0029] The sludge to be treated is activated sludge or digested sludge with a water content of less than 95%.

[0030] In the long-term research, the inventors of the present application found that the modified tannin flocculant can combine the advantages of tannic acid and poly(dimethyldiallylammonium chloride). The reasons are as follows: The phenolic hydroxyl groups and hydroxyl groups of tannin can combine with the hydrogen bonds and ionic bonds on the amino acid residues of proteins. At the same time, there are many benzene ring structures. The benzene ring has hydrophobicity and can form non-covalent bonds with proteins, which can change the protein from the original unfolded state to the folded state, and at the same time cause cross-linking between molecules to form a gel-like structure, squeezing out the water in the intracellular tissue. Poly(dimethyldiallylammonium chloride) is a pure cationic organic polymer. In addition to the bridging and sweeping functions of general polymer flocculants, it also has a relatively strong ability to dissolve extracellular polymers and electrical neutralization. The micro-crosslinked modified flocculant copolymerized from tannin and dimethyldiallylammonium chloride not only combines the advantages of the two substances, but also in the flocculation process, the micro-crosslinked molecular structure can make full use of the spatial extension advantage to adsorb suspended solid particles, and the formed flocs have high density and good sedimentation performance.

[0031] The present invention has the following beneficial effects:

[0032] The present invention provides a sludge deep conditioning agent composition. By using a cell wall breaker, a protein astringent, and a modified tannin flocculant as raw materials and carrying out appropriate weight ratios, the finally prepared sludge deep conditioning agent composition can fully release the internal and external water of the sludge and improve the dehydration efficiency. The sludge conditioning agent composition of the present invention has a high degree of designability. During the conditioning process of excess sludge, the dosage of the agent is small and the dehydration effect is good. The molecular chain of the sludge deep conditioning agent composition of the present invention has a high density of cationic charges and strong electrical neutralization and adsorption capabilities, and has a good flocculation effect, and can be applied to the conditioning of excess sludge. Detailed Embodiments

[0033] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0034] First, the present invention provides a sludge deep conditioning agent composition, and the raw material components include:

[0035] Cell wall breaker, 5-20 parts by weight;

[0036] Protein astringent, 20-60 parts by weight;

[0037] Modified tannin flocculant, 20-60 parts by weight.

[0038] Preferably, the cell wall breaker is any one or more of potassium ferrate, potassium permanganate, and sodium percarbonate.

[0039] Preferably, the protein coagulant is any one or more of aluminum sulfate, zinc carbonate, and sodium humate.

[0040] Preferably, the modified tannin flocculant is a product copolymerized from tannin, dimethyldiallylammonium chloride, and N,N'-methylenebisacrylamide.

[0041] Furthermore, the present invention also provides a method for preparing the modified tannin flocculant, which is specifically as follows:

[0042] (a) By mass, 2-8 parts of tannin, 200-600 parts of dimethyldiallylammonium chloride, 1-3 parts of N,N'-methylenebisacrylamide, and 130-400 parts of distilled water are used to obtain a monomer solution;

[0043] Add 0.1-0.5 parts of chelating agent to the monomer solution, and mix and dissolve thoroughly under stirring conditions, and deoxygenate by passing nitrogen;

[0044] (b) By mass, slowly add 0.03-0.5 parts of initiator to the solution system obtained in step (a) to initiate polymerization, and after the system temperature rises to 50-60 °C, keep it warm for 2-6 h to obtain an aqueous solution of the modified tannin flocculant.

[0045] Preferably, in step (a), the dimethyldiallylammonium chloride is an aqueous solution of dimethyldiallylammonium chloride with a mass percentage content of 60%-65%.

[0046] Preferably, in step (a), in the monomer solution, the total solid content of tannin, dimethyldiallylammonium chloride, and N,N'-methylenebisacrylamide is 35 wt%-45 wt%.

[0047] Preferably, in step (a), the chelating agent is a mixture composed of disodium ethylenediaminetetraacetate and diethylenetriamine pentamethylenephosphonic acid in a mass ratio of 2:(1-3);

[0048] The initiator is any one or more of potassium persulfate, ammonium persulfate, ammonium cerium nitrate, and azobisisobutyramidine hydrochloride;

[0049] The viscosity of the aqueous solution of the modified tannin flocculant is above 100,000 cps, and the solid content concentration is 40%.

[0050] Furthermore, the present invention also provides a method for deeply dehydrating sludge by using the sludge deep conditioning agent composition, including the following steps:

[0051] S1. Add the cell wall breaker to the sludge to be treated and stir until fully mixed. The dosage of the cell wall breaker is 0.5%-1% of the dry weight of the sludge.

[0052] S2. Add the protein coagulant to the sludge treated in step (S1) and stir until fully mixed. The dosage of the protein coagulant is 1%-5% of the dry weight of the sludge.

[0053] S3. Add the modified tannin flocculant to the sludge treated in step (S2) and stir until fully mixed. The dosage of the modified tannin flocculant is 1%-5% of the dry weight of the sludge.

[0054] S4. Let the sludge treated in step (S3) stand in the conditioning tank for 10-15 minutes, and then perform pressure filtration and dehydration, thus completing the deep dehydration of the sludge.

[0055] Preferably, the specific operating conditions for the pressure filtration and dehydration are: perform pressure filtration treatment at a pressure of 0.8-1.5 MPa for 30-40 minutes to complete the pressure filtration.

[0056] The filter press is a plate and frame filter press.

[0057] The sludge to be treated is activated sludge or digested sludge with a moisture content of less than 95%.

[0058] In the following examples, 1 part by weight represents 1 g.

[0059] Example 1

[0060] This example provides a sludge deep conditioning agent composition, and the raw material components include:

[0061] Potassium ferrate, 25 parts by weight;

[0062] Sodium humate first-grade product with an effective content of 70%, 100 parts by weight;

[0063] Aqueous solution of modified tannin flocculant, 250 parts by weight.

[0064] The specific preparation method of the modified tannin flocculant is as follows:

[0065] (a) By mass, add 3 parts of tannin, 500 parts of an aqueous solution of dimethyldiallylammonium chloride with a mass concentration of 65%, 1 part of N,N-methylenebisacrylamide, and 318.5 parts of distilled water to the reaction kettle to prepare a monomer solution with a solid content concentration of 40%. Then add 0.2 parts of disodium ethylenediaminetetraacetate and 0.1 part of diethylenetriamine pentamethylenephosphonic acid, fully mix and dissolve, and purge with nitrogen to remove oxygen under stirring;

[0066] (b) By mass fraction, 0.1 part of ammonium cerium nitrate and 0.2 part of azobisisobutyramidine hydrochloride are slowly added to the solution system obtained in step (a) to initiate polymerization. After the system temperature rises to 50 °C, keep it warm for 3 h to obtain an aqueous solution of the modified tannin flocculant, with a rotational viscosity of 11,500 cps and a solid content concentration of 40%.

[0067] Further, a method for deeply dewatering sludge using the sludge deep conditioning agent composition includes the following steps:

[0068] S1. Add 25 g of potassium ferrate to 100 kg of sludge to be treated with a water content of 95% (excess sludge from Beikong Water Service Yanjiao West Water Plant), and stir until fully mixed;

[0069] S2. Add 100 g of first-grade sodium humate with an effective content of 70% to the sludge treated in step (S1), and stir until fully mixed;

[0070] S3. Add 250 g of the aqueous solution of the modified tannin flocculant with a solid content concentration of 40% to the sludge treated in step (S2), and stir until fully mixed;

[0071] S4. Let the sludge treated in step (S3) stand in the conditioning tank for 10 min, then draw out the concentrated sludge from the bottom of the tank, introduce it into a plate and frame filter press for pressure filtration and dewatering, keep it under a pressure of 1.5 MPa for 40 min, and the pressure filtration is completed, that is, the deep dewatering of the sludge to be treated is completed. Detect the dewatering effect, and the water content of the dewatered sludge cake is 53.26%.

[0072] Example 2

[0073] This example provides a sludge deep conditioning agent composition, and the raw material components include:

[0074] Potassium permanganate, 25 parts by weight;

[0075] First-grade sodium humate with an effective content of 70%, 100 parts by weight;

[0076] Aqueous solution of modified tannin flocculant, 250 parts by weight.

[0077] The preparation method of the modified tannin flocculant is specifically as follows:

[0078] (a) By mass fraction, add 3 parts of tannin, 500 parts of an aqueous solution of dimethyldiallylammonium chloride with a mass concentration of 65%, 1 part of N,N-methylenebisacrylamide, and 318.5 parts of distilled water into a reaction kettle together to prepare a monomer solution with a solid content concentration of 40%. Then add 0.2 part of disodium ethylenediaminetetraacetate and 0.1 part of diethylenetriamine pentamethylenephosphonic acid, fully mix and dissolve, and deoxygenate by passing nitrogen under stirring;

[0079] (b) By mass parts, 0.1 part of ammonium cerium nitrate and 0.2 part of azobisisobutyramidine hydrochloride are slowly added to the solution system obtained in step (a) to initiate polymerization. After the temperature of the system rises to 50 °C, keep it warm for 3 h to obtain an aqueous solution of the modified tannin flocculant with a rotational viscosity of 11,500 cps and a solid content concentration of 40%.

[0080] Further, a method for deeply dewatering sludge using the sludge deep conditioning agent composition includes the following steps:

[0081] S1. Add 25 g of potassium permanganate to 100 kg of sludge to be treated with a water content of 95% (excess sludge from Beikong Water Service Yanjiao West Water Plant), and stir until fully mixed;

[0082] S2. Add 100 g of sodium humate of first grade with an effective content of 70% to the sludge treated in step (S1), and stir until fully mixed;

[0083] S3. Add 250 g of the aqueous solution of the modified tannin flocculant with a solid content concentration of 40% to the sludge treated in step (S2), and stir until fully mixed;

[0084] S4. Let the sludge treated in step (S3) stand in the conditioning tank for 10 min, then draw out the concentrated sludge from the bottom of the tank, introduce it into a plate and frame filter press for pressure filtration and dewatering, keep it under a pressure of 1.5 MPa for 40 min, and the pressure filtration is completed, that is, the deep dewatering of the sludge to be treated is completed. Detect the dewatering effect, and the water content of the dewatered sludge cake is 52.45%.

[0085] Example 3

[0086] This example provides a sludge deep conditioning agent composition, and the raw material components include:

[0087] Potassium ferrate, 25 parts by weight;

[0088] Aluminum sulfate, 75 parts by weight;

[0089] Aqueous solution of modified tannin flocculant, 250 parts by weight.

[0090] The preparation method of the modified tannin flocculant is specifically as follows:

[0091] (a) By mass parts, add 3 parts of tannin, 500 parts of an aqueous solution of dimethyldiallylammonium chloride with a mass concentration of 65%, 1 part of N,N - methylenebisacrylamide, and 318.5 parts of distilled water into a reaction kettle to prepare a monomer solution with a solid content concentration of 40%. Then add 0.2 part of disodium ethylenediaminetetraacetate and 0.1 part of diethylenetriamine pentamethylenephosphonic acid, fully mix and dissolve, and purge with nitrogen to remove oxygen under stirring;

[0092] (b) By mass fraction, 0.1 part of ammonium cerium nitrate and 0.2 part of azobisisobutyramidine hydrochloride are slowly added to the solution system obtained in step (a) to initiate polymerization. After the system temperature rises to 50 °C, keep it warm for 3 h to obtain an aqueous solution of the modified tannin flocculant, with a rotational viscosity of 115,000 cps and a solid content concentration of 40%.

[0093] Further, a method for deeply dewatering sludge using the sludge deep conditioning agent composition includes the following steps:

[0094] S1. Add 25 g of potassium ferrate to 100 kg of sludge to be treated with a water content of 95% (excess sludge from Beikong Water Service Yanjiao West Water Plant), and stir until fully mixed;

[0095] S2. Add 75 g of aluminum sulfate to the sludge treated in step (S1), and stir until fully mixed;

[0096] S3. Add 250 g of the aqueous solution of the modified tannin flocculant with a solid content concentration of 40% to the sludge treated in step (S2), and stir until fully mixed;

[0097] S4. Let the sludge treated in step (S3) stand in the conditioning tank for 10 min, then draw out the concentrated sludge from the bottom of the tank, introduce it into a plate and frame filter press for pressure filtration and dewatering, keep it under a pressure of 1.5 MPa for 40 min, and the pressure filtration is completed, that is, the deep dewatering of the sludge to be treated is completed. Detect the dewatering effect, and the water content of the dewatered sludge cake is 54.62%.

[0098] Example 4

[0099] This example provides a sludge deep conditioning agent composition, and the raw material components include:

[0100] Potassium permanganate, 25 parts by weight;

[0101] Aluminum sulfate, 75 parts by weight;

[0102] Aqueous solution of modified tannin flocculant, 250 parts by weight.

[0103] The preparation method of the modified tannin flocculant is specifically as follows:

[0104] (a) By mass fraction, add 7 parts of tannin, 600 parts of an aqueous solution of dimethyldiallylammonium chloride with a mass concentration of 60%, 3 parts of N,N - methylenebisacrylamide, and 315 parts of distilled water into a reaction kettle together to prepare a monomer solution with a solid content concentration of 40%. Then add 0.1 part of disodium ethylenediaminetetraacetate and 0.2 part of diethylenetriamine pentamethylenephosphonic acid, fully mix and dissolve, and pass nitrogen to remove oxygen under stirring;

[0105] (b) By mass, 0.1 part of ammonium cerium nitrate and 0.2 part of azobisisobutyramidine hydrochloride are slowly added to the solution system obtained in step (a) to initiate polymerization. After the system temperature rises to 60 °C, keep it warm for 6 h to obtain an aqueous solution of the modified tannin flocculant with a rotational viscosity of 165,000 cps and a solid content concentration of 40%.

[0106] Furthermore, a method for deeply dewatering sludge using the sludge deep conditioning agent composition includes the following steps:

[0107] S1. Add 25 g of potassium permanganate to 100 kg of sludge to be treated with a water content of 95% (excess sludge from Yanjiao West Water Plant of Beijing Enterprises Water Group Co., Ltd.), and stir until fully mixed;

[0108] S2. Add 75 g of aluminum sulfate to the sludge treated in step (S1), and stir until fully mixed;

[0109] S3. Add 250 g of the aqueous solution of the modified tannin flocculant with a solid content concentration of 40% to the sludge treated in step (S2), and stir until fully mixed;

[0110] S4. Let the sludge treated in step (S3) stand in the conditioning tank for 10 min, then draw out the concentrated sludge from the bottom of the tank, introduce it into a plate and frame filter press for pressure filtration and dewatering, keep it at a pressure of 1.5 MPa for 40 min, and the pressure filtration is completed, that is, the deep dewatering of the sludge to be treated is completed. Detect the dewatering effect, and the water content of the dewatered sludge cake is 51.25%.

[0111] Comparative Example 1

[0112] This comparative example provides a method for dehydrating sludge using a conventional inorganic sludge conditioner (a mixture of ferric chloride and lime). Specifically, the dosage of ferric chloride is 6.12% of the dry weight of the sludge, and the dosage of lime is 24% of the dry weight of the sludge. After treatment with the same plate and frame filter press at a pressure of about 1.5 MPa and a pressing time of 40 min, the water content of the sludge cake is 58.56%.

[0113] Comparative Example 2

[0114] This comparative example provides a method for dehydrating sludge using potassium permanganate, sodium humate, and poly(dimethyldiallylammonium chloride). Specifically:

[0115] S1. Add 25 g of potassium ferrate to 100 kg of sludge to be treated with a water content of 95% (excess sludge from Yanjiao West Water Plant of Beijing Enterprises Water Group Co., Ltd.), and stir until fully mixed;

[0116] S2. Add 75 g of aluminum sulfate to the sludge treated in step (S1), and stir until fully mixed;

[0117] S3. Add 250 g of an aqueous solution of polydimethyldiallylammonium chloride with a solid content concentration of 40% to the sludge after the treatment in step (S2), and stir until fully mixed.

[0118] S4. Let the sludge after the treatment in step (S3) stand in the conditioning tank for 10 min, then draw out the concentrated sludge from the bottom of the tank, introduce it into the same plate-and-frame filter press for pressure filtration and dehydration, maintain it at a pressure of 1.5 MPa for 40 min, and after the pressure filtration is completed, the deep dehydration of the sludge to be treated is completed. Detect the dehydration effect, and the moisture content of the dewatered sludge cake is 56.36%.

[0119] Comparative Example 3

[0120] This comparative example provides a method for dehydrating sludge using potassium permanganate and the aqueous solution of the modified tannin flocculant, specifically:

[0121] S1. Add 45 g of potassium permanganate to 100 kg of sludge to be treated with a moisture content of 95% (the excess sludge of Beikong Water Service Yanjiao West Water Plant), and stir until fully mixed.

[0122] S2. Add 300 g of the aqueous solution of the modified tannin flocculant with a solid content concentration of 40% to the sludge after the treatment in step (S1), and stir until fully mixed.

[0123] S4. Let the sludge after the treatment in step (S3) stand in the conditioning tank for 10 min, then draw out the concentrated sludge from the bottom of the tank, introduce it into the same plate-and-frame filter press for pressure filtration and dehydration, maintain it at a pressure of 1.5 MPa for 40 min, and after the pressure filtration is completed, the deep dehydration of the sludge to be treated is completed. Detect the dehydration effect, and the moisture content of the dewatered sludge cake is 57.53%.

[0124] Comparative Example 4

[0125] This comparative example provides a method for dehydrating sludge using aluminum sulfate and the aqueous solution of the modified tannin flocculant, specifically:

[0126] S1. Add 100 g of aluminum sulfate to 100 kg of sludge to be treated with a moisture content of 95% (the excess sludge of Beikong Water Service Yanjiao West Water Plant), and stir until fully mixed.

[0127] S2. Add 300 g of the aqueous solution of the modified tannin flocculant with a solid content concentration of 40% to the sludge after the treatment in step (S1), and stir until fully mixed.

[0128] S4. Let the sludge treated in step (S3) stand still in the conditioning tank for 10 min, then draw out the concentrated sludge from the bottom of the tank and introduce it into the same plate-and-frame filter press for pressure filtration and dehydration. Keep it under a pressure of 1.5 MPa for 40 min. After the pressure filtration is completed, the deep dehydration of the sludge to be treated is completed. Detect the dehydration effect. The moisture content of the filter cake after dehydration is 58.17%.

[0129] Experimental example

[0130] Detect the sludge dehydration effects of different flocculants obtained in Examples 1-4 and Comparative Examples 1-4. The results are shown in Table 1.

[0131] Table 1 - Comparison of sludge dehydration effects of different flocculants

[0132] Sample Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Dosage proportion in dry mud % 3.9 3.9 4.0 4.0 30.12 4.0 3.3 4.4 Moisture content of mud cake % 53.26 52.45 54.62 51.25 58.56 56.36 57.53 58.17

[0133] As can be seen from Table 1, the sludge deep conditioning agent composition of the present invention has a better sludge dehydration effect than similar products, can completely replace conventional inorganic sludge conditioning agents, greatly improves the calorific value of the sludge, and helps to promote the resource utilization of the sludge. Compared with conventional inorganic conditioning agents, the dosage of the agent accounts for more than 30% of the dry weight of the sludge. The dosage of the present invention is small, only about 4% of the weight of the dry sludge, which will greatly reduce the sludge disposal cost. If any one of the three components of the cell wall breaker, protein astringent, and modified tannin flocculant in the sludge deep conditioning agent composition of the present invention is missing, it will affect the deep dehydration effect of the sludge (see Comparative Examples 2-4 for details), indicating that only under the combined action of the above three components can the dehydration effect of the conditioning agent composition of the present invention on the sludge reach the best.

Claims

1. A sludge deep conditioning agent composition, characterized in that: The raw material components include: Cell wall disrupting agent, 5-20 parts by weight; Protein astringent, 20-60 parts by weight; Modified tannin flocculant, 20-60 parts by weight; The cell wall disrupting agent is any one or more of potassium ferrate, potassium permanganate, and sodium percarbonate; The protein astringent is any one or more of aluminum sulfate, zinc carbonate, and sodium humate; The modified tannin flocculant is a product obtained by copolymerization of tannin, dimethyl diallyl ammonium chloride and N,N-methylenebisacrylamide; The preparation method of the modified tannin flocculant is specifically as follows: (a) adding 2-8 parts of tannin, 200-600 parts of dimethyldiallylammonium chloride, 1-3 parts of N,N-methylenebisacrylamide and 130-400 parts of distilled water, by mass, to obtain a monomer solution; Add 0.1-0.5 parts of chelating agent to the monomer solution, mix and dissolve thoroughly under stirring, and pass nitrogen to remove oxygen; The dimethyldiallyl ammonium chloride is a dimethyldiallyl ammonium chloride aqueous solution with a mass percentage of 60%-65%; In the monomer solution, the total solid content of tannin, dimethyldiallylammonium chloride and N,N-methylenebisacrylamide is 35wt%-45wt%; The chelating agent is a mixture of disodium ethylenediaminetetraacetate and diethylenetriaminepenta(methylenephosphonic acid) in a mass ratio of 2:(1-3); (b) slowly adding 0.03-0.5 parts by weight of an initiator to the solution system obtained in step (a) to initiate polymerization, and after the system temperature rises to 50-60° C., the temperature is maintained for 2-6 hours to obtain a modified tannin flocculant aqueous solution; The initiator is any one or more of potassium persulfate, ammonium persulfate, ammonium cerium nitrate, and azobisisobutyramidine hydrochloride; The viscosity of the modified tannin flocculant aqueous solution is above 100,000 cps.

2. A method for deep dehydration using the sludge deep conditioner composition according to claim 1, characterized in that: The following steps are involved: S1. Add the cell wall disrupting agent to the sludge to be treated and stir until fully mixed; The dosage of the cell wall disrupting agent is 0.5%-1% of the dry weight of the sludge; S2, adding a protein astringent to the sludge treated in step (S1), and stirring until fully mixed; the amount of the protein astringent added is 1%-5% of the dry weight of the sludge; S3, adding a modified tannin flocculant to the sludge treated in step (S2), and stirring until fully mixed; the dosage of the modified tannin flocculant is 1%-5% of the dry weight of the sludge; S4. The sludge treated in step (S3) is allowed to stand in a conditioning tank for 10-15 minutes, and then subjected to filter pressing and dehydration, thereby completing deep dehydration of the sludge.

3. The deep dehydration method according to claim 2, characterized in that: The specific operating conditions of the filter pressing dehydration are: the filter pressing treatment is carried out at a pressure of 0.8-1.5MPa for 30-40min, and the filter pressing is completed; The filter press is a plate and frame filter press; The sludge to be treated is activated sludge or digested sludge with a moisture content of less than 95%.