Sludge conditioner, preparation method and application thereof in improving sludge dewatering degree

Abstract

The application discloses a sludge conditioner, a preparation method and application of the sludge conditioner in improving sludge dewatering degree, and belongs to the technical field of sludge dewatering, and comprises the following components in parts by weight: moringa extract 15-25 parts, dry yeast powder 2-5 parts, tannic acid 10-15 parts, LS-g-CPA 20-35 parts, CS-g-PAO 20-35 parts, mercaptoethanol 1-2 parts and lysozyme 1-2 parts. The sludge dewatering degree can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of sludge dewatering, in particular to a sludge conditioner, a preparation method and application thereof in improving sludge dewatering degree. BACKGROUND

[0002] The municipal sewage sludge treatment is an important part of sewage treatment, and the treatment and disposal degree is an important standard for evaluating the sewage treatment condition. If the sewage sludge treatment and disposal effect is poor, not only the environment will be polluted, but also the resources will be wasted. The municipal sewage sludge has high water content, generally about 95%, and poor dewatering performance. Studies show that the water contained in the sludge can be roughly divided into four categories. The free water, i.e. the inter-particle void water, accounts for about 70% of the total water, the capillary water, i.e. the water in the inter-particle capillary, accounts for about 20%, and the attached water, i.e. the water adsorbed by the sludge particles and the internal water in the microbial particles, accounts for about 10%. Since the inter-particle void water is the main component of the sludge, and does not interact with the sludge solids, it can be removed by simple concentration or using very small mechanical force. The other types of water have a certain "force" interaction with the sludge particles, although they only account for a small part in the sludge, but their content is still far more than the content of solid matter, and they cannot be removed by mechanical force.

[0003] The residual activated sludge is one of municipal sewage sludge, mainly composed of suspended sludge flocs, and the sludge flocs are composed of a large number of dispersed microorganism bacteria bridged by extracellular polymer substances (EPS), cations such as calcium and magnesium ions and other fine particles. The EPS is an important component of the floc matrix, mainly produced by the metabolism of microorganisms in the sludge, and is a substance that can aggregate bacteria to form sludge flocs and is the main component of the sludge floc matrix. The EPS of the activated sludge accounts for up to 5% of the dry weight of the sludge. The total EPS in the floc accounts for about 80% of the total organic matter in the sludge. The EPS can be divided into two parts: tightly adhered extracellular polymer and loosely adhered extracellular polymer. The tightly adhered extracellular polymer is tightly combined with the cell surface, stably adsorbed outside the cell wall, and has a certain shape located in the outer layer. The loosely adhered extracellular polymer has a relatively loose structure and can diffuse to the surrounding environment without obvious edge. The EPS is composed of polysaccharides, proteins, nucleic acids, humus, oils and heteropolymers, among which polysaccharides, proteins and nucleic acids are the main components of EPS, which can capture water and increase the viscosity of sludge. Some studies have shown that EPS has an important influence on the settling and dewatering performance of activated sludge. One reason why sludge is difficult to dewater is that EPS surrounds the bacteria like a capsule and continuously secretes viscous polymers into the surrounding solution. Because the amount of EPS increases, more water is embedded in the sludge flocs and is difficult to remove by mechanical filtration. In fact, although it has been reported that a larger amount of EPS is not conducive to the dewatering performance of sludge, it has been proved elsewhere that it is not the amount of EPS, but its "quality" (property and composition) that improves its dewatering performance.

[0004] Traditional sludge dewatering methods include heat treatment, ultrasonic wave, pressure filtration, deep oxidation and alkali treatment. These methods not only increase the operation cost of sludge treatment, but also cause secondary pollution due to the addition of flocculants and conditioners, and cannot affect the property and composition of EPS. After sludge dewatering treatment, the water content is always more than 10%, and the degree of sludge dewatering cannot be improved.

[0005] Therefore, developing a low-cost technology that can improve the degree of sludge dewatering has become an urgent problem faced by the sludge treatment industry today. SUMMARY

[0006] In order to overcome the shortcomings of the prior art, one of the purposes of the present application is to provide a sludge conditioner which can improve the degree of sludge dewatering.

[0007] The second purpose of the present application is to provide a sludge conditioner which has a simple preparation method, is easy to operate and has low cost.

[0008] The third object of the present application is to provide an application of the sludge conditioner in deep dewatering of sludge, which can improve the degree of sludge dewatering.

[0009] One of the objects of the present application is achieved by adopting the following technical solutions:

[0010] A sludge conditioner, comprising the following components in parts by weight: 15-25 parts of moringa extract, 2-5 parts of dry yeast powder, 10-15 parts of tannic acid, 20-35 parts of LS-g-CPA, 20-35 parts of CS-g-PAO, 1-2 parts of mercaptoethanol, and 1-2 parts of lysozyme.

[0011] Further, the preparation method of the moringa extract is as follows: moringa seeds are dried in an oven at 45 DEG C for 48 h, and then mixed and ground into fine powder to obtain the moringa extract.

[0012] Further, the preparation method of the CS-g-PAO comprises the following steps:

[0013] S1, fully dissolving chitosan in an acetic acid solution with a mass percentage of 1.0 wt%, and stirring to obtain a chitosan solution with a mass percentage of 3.0 wt%, and placing in a hot glass reaction container for standby;

[0014] S2, adding AO in an equal molar amount of the chitosan into the hot glass reaction container, and stirring uniformly;

[0015] S3, at room temperature, blowing nitrogen into the hot glass reaction container for 10 min to remove oxygen in the hot glass reaction container, and then adding 2,20-azo[2-(2-imidazoline-2-yl)propane] dihydrochloride into the mixed solution;

[0016] S4, using an ultraviolet light with a power of 500 W and an intensity of 11.7 x 10 2 μw / cm 2 for uniform irradiation of the hot glass reaction container until the polymerization reaction is completed, to obtain a gel product;

[0017] S5, purifying the obtained gel product with acetone and anhydrous ethanol, removing organic monomers and homopolymer PAO with a Soxhlet extraction device (a mixture of formamide-acetic acid at 1:1) and anhydrous ethanol after purification, and drying in a vacuum oven to obtain a pure graft copolymer CS-g-PAO.

[0018] Further, the preparation method of the LS-g-CPA comprises the following steps:

[0019] S1, adding cationic monomers AM and DMC into a three-necked flask in a molar ratio of 1:1, and then adding a chain transfer agent 4-vinyl benzyl chloride, and reacting at 55 DEG C for 30 min;

[0020] S2, re-add APS, 60 DEG C, reaction 6h, after the reaction, the product is placed at room temperature, purified with 3 times the mass of ethanol, get light yellow product, freeze drying 12h, get pure CPA;

[0021] S3, LS as the skeleton and the prepared pure CPA graft copolymerization, LS and CPA are added to a three-necked flask containing 1mol / L NaOH, 70 DEG C, reaction 4 hours, after the reaction is completed, the product is placed at room temperature, extracted with acetone 3 times, get brown product, dialysis 72h, rotary evaporation, freeze drying 24h get purified LS-g-CPA.

[0022] Further, the dry yeast powder is made of Candida tropicalis.

[0023] The second purpose of the application is realized by the following technical scheme:

[0024] A preparation method of a sludge conditioner comprises the following steps:

[0025] S1, according to the formula amount of moringa extract, tannic acid, LS-g-CPA, CS-g-PAO, mercaptoethanol is mixed uniformly, then is packed into small bags;

[0026] S2, according to the formula amount of lysozyme, dry yeast powder, is separately packed into small bags;

[0027] S3, when used, the components in the three bags are mixed together to obtain the sludge conditioner.

[0028] The third purpose of the application is realized by the following technical scheme:

[0029] The application of a sludge conditioner in sludge deep dewatering comprises the following steps: according to the amount of sludge, the mass fraction of 5% of the sludge conditioner is added to the sludge, and the sludge is mixed uniformly and conditioned.

[0030] Compared with the prior art, the application has the following advantages:

[0031] The sludge conditioner provided by the application can degrade peptidoglycan, destroy the structure of bacterial cell wall, weaken the adhesion ability of extracellular polymeric substance (EPS) adhered to the cell wall destruction, make the EPS on the surface of sludge flocculation fall off and dissolve in the solution, change the morphology of sludge flocculation, and significantly improve the permeability of the cell wall, which is beneficial to the release of internal water in the bacteria; the addition of moringa can effectively reduce the negative charge on the surface of sludge flocculation, reduce the repulsion between sludge extracellular polymers and between sludge flocculation, achieve the effect of destabilization, facilitate the aggregation of sludge flocculation and precipitation, reduce the adsorption of water on the surface of sludge flocculation, and the cationic groups of LS-g-CPA (sodium polyacrylamide grafted lignin sulfonate) effectively reduce the hydrophilic functional groups of EPS, such as hydroxyl, lactone and carboxyl, reduce the hydrophilicity of sludge EPS, and facilitate the release of bound water in the flocculation structure of sludge; in addition, the quaternary ammonium group promotes the destruction of EPS and sludge flocculation, leading to the exposure of a large number of hydrophobic amino acids, increasing the hydrophobicity of sludge flocculation, and the octopus-like skeleton structure of LS-g-CPA establishes good drainage channels in the sludge flocculation structure, and the CS-g-PAO has rich hydrophobic regions, which is incompatible with sludge particles, helping to form more drainage channels in sludge flocculation, which is beneficial to the drainage of water difficult to release in sludge, these drainage channels can greatly improve the filterability and compressibility of sludge, further, the yeast can combine with EPS and continuously secrete acid protease and alpha-amylase in EPS, degrade the protein and polysaccharide in EPS, make the macromolecular hydrophilic organic matter into small molecular weight organic matter, mercaptoethanol can destroy the disulfide bond of protein, the protein loses the secondary structure, so that the internal hydrophobic group is more easily exposed, and the bound water in the sludge is further released, at the same time, tannic acid precipitates with protein by acting with the hydrophobic group, reduces the protein content of extracellular polymeric substance, thereby effectively reducing the bound water content in EPS, the functions of the above components are related, and the synergistic effect improves the dewatering degree of sludge.

[0032] The application provides a sludge conditioner in the application of sludge deep dewatering, and the sludge conditioner is convenient to use and has obvious use effect. DETAILED DESCRIPTION

[0033] The application will be further described below in combination with specific embodiments, and it should be noted that the embodiments described below or the technical features can be combined to form new embodiments without conflict.

[0034] The raw materials used in the following examples are as follows:

[0035] Chitosan (CS, 95% deacetylation, viscosity 100e 200mpa.s) is purchased from Shanghai Maikelin Biotechnology Co., Ltd.;

[0036] Acryloyloxyethyl dimethyl benzyl ammonium chloride (AO, 80%) was purchased from Wuhan Yihua Cheng Science and Technology Development Co., Ltd.; initiator 2, 20-azo [2- (2-imidazoline-2-yl) propane] dihydrochloride (VA-044, AR) was purchased from Chongqing Lanjie Guangshun Water Purification Material Co., Ltd.;

[0037] Cationic monomer acrylamide (AM), methacryloyloxyethyl trimethyl ammonium chloride (DMC), ammonium persulfate (APS), 4-vinyl chlorobenzene, sodium lignosulfonate (LS) were all purchased from Shanghai Maikelin Biochemical Technology Co., Ltd.

[0038] The detection instrument used in experimental example 2 is as follows:

[0039] The dilatometer was purchased from Shanghai Haoyuan Optoelectronic Equipment Co., Ltd.

[0040] Example 1

[0041] The sludge conditioner provided in this example includes the following components by weight: 20 parts of moringa extract, 5 parts of dry yeast powder, 10 parts of tannic acid, 30 parts of LS-g-CPA (sodium lignosulfonate grafted with polyacrylamide), 25 parts of CS-g-PAO, 1 part of mercaptoethanol, and 1 part of lysozyme.

[0042] The preparation method of the sludge conditioner provided in this example is as follows: including the following steps:

[0043] S1, the moringa extract, tannic acid, LS-g-CPA, CS-g-PAO, and mercaptoethanol are weighed according to the formula amount, mixed uniformly, and then packaged into small bags;

[0044] S2, the lysozyme and dry yeast powder are weighed according to the formula amount and packaged into small bags separately;

[0045] S3, when used, the components in the three bags are mixed together to obtain the sludge conditioner.

[0046] Further, the preparation method of the moringa extract is as follows: the moringa seeds are dried in an oven at 45℃ for 48h, then mixed and ground into fine powder to obtain the moringa extract.

[0047] The preparation method of the CS-g-PAO includes the following steps: S1, the chitosan is fully dissolved in a 1.0wt% acetic acid solution, and a 3.0wt% chitosan solution is obtained by vigorous stirring, and is placed in a hot glass reaction container for standby;

[0048] S2, the same molar amount of AO as the chitosan is added to the hot glass reaction container and stirred uniformly;

[0049] S3, at room temperature, by blowing nitrogen into the hot glass reaction vessel for 10 min to remove oxygen in the hot glass reaction vessel, and then adding VA-044 into the mixed solution;

[0050] S4, using a power of 500W, a light intensity of 11.7x10 2 μw / cm 2 of ultraviolet light to uniformly irradiate the hot glass reaction vessel until the polymerization reaction is completed, to obtain a gel product;

[0051] S5, the obtained gel product is purified with acetone and anhydrous ethanol, after purification, the organic monomer, homopolymer PAO is removed by Soxhlet extraction device (formamide-acetic acid mixture 1:1) and anhydrous ethanol, and dried in a vacuum oven to obtain a pure graft copolymer CS-g-PAO.

[0052] The preparation method of the LS-g-CPA comprises the following steps: S1, adding cationic monomer AM and DMC into a three-necked flask in a molar ratio of 1:1, and then adding chain transfer agent 4-vinyl benzyl chloride, reacting at 55℃ for 30 min;

[0053] S2, adding APS, reacting at 60℃ for 6h, after the reaction is completed, placing the product at room temperature, purifying with 3 times the mass of ethanol to obtain a light yellow product, and freeze-drying for 12h to obtain pure CPA;

[0054] S3, graft copolymerization of LS as a skeleton with the prepared pure CPA, adding LS and CPA into a three-necked flask containing 1 mol / L NaOH, reacting at 70℃ for 4h, after the reaction is completed, placing the product at room temperature, extracting with acetone for 3 times to obtain a brown product, and dialyzing for 72h, rotary evaporating, and freeze-drying for 24h to obtain purified LS-g-CPA.

[0055] The dry yeast powder is a dry powder prepared from Candida tropicalis.

[0056] A circle of yeast colonies on an agar slant is inoculated into a sterilized yeast extract-glucose YPD liquid medium in a flask, the flask is placed in a constant temperature shaker, and cultured at 28℃ and 175 rpm for 48h to harvest a yeast cell suspension, the cell suspension is centrifuged at 8000 rpm for 5 min, the supernatant is discarded, and the yeast precipitate is harvested and spray-dried to obtain a dry yeast powder.

[0057] After the yeast is cultured for 48h, the YPD supernatant contains relevant acid protease, alpha-amylase and cellulase.

[0058] Example 2

[0059] The embodiment provides a sludge conditioner, which comprises the following components in parts by weight: moringa extract 15 parts, dry yeast powder 3 parts, tannic acid 15 parts, LS-g-CPA 20 parts, CS-g-PAO 35 parts, mercaptoethanol 2 parts, and lysozyme 2 parts.

[0060] The embodiment provides a preparation method of a sludge conditioner, which comprises the following steps:

[0061] S1, moringa extract, tannic acid, LS-g-CPA, CS-g-PAO and mercaptoethanol are weighed according to the formula amount, uniformly mixed, and then packaged into small bags;

[0062] S2, lysozyme and dry yeast powder are weighed according to the formula amount, and are separately packaged into small bags;

[0063] S3, when used, the components in the three bags are mixed together to obtain the sludge conditioner.

[0064] Further, the preparation method of the moringa extract is as follows: moringa seeds are dried in an oven at 45 DEG C for 48 h, and then are mixed and ground into fine powder to obtain the moringa extract.

[0065] The preparation method of the CS-g-PAO comprises the following steps: S1, chitosan is fully dissolved in an acetic acid solution with a mass percentage of 1.0 wt%, and is stirred to obtain a chitosan solution with a mass percentage of 3.0 wt%, and is placed in a hot glass reaction container for standby;

[0066] S2, AO in an equal molar amount of the chitosan is added into the hot glass reaction container and is uniformly stirred;

[0067] S3, oxygen in the hot glass reaction container is removed by blowing nitrogen into the hot glass reaction container for 10 min at normal temperature, and then VA-044 is added into the mixed solution;

[0068] S4, the hot glass reaction container is uniformly irradiated by ultraviolet light with a power of 500 W and an intensity of 11.7x10 2 μw / cm 2 ; and the polymerization reaction is completed to obtain a gel product;

[0069] S5, the obtained gel product is purified by acetone and anhydrous ethanol, the organic monomer and the homopolymer PAO are removed by a Soxhlet extraction device (a mixture of formamide-acetic acid with a ratio of 1:1) and anhydrous ethanol after purification, and the pure graft copolymer CS-g-PAO is obtained by drying in a vacuum oven.

[0070] The preparation method of the LS-g-CPA comprises the following steps: S1, adding cationic monomers AM and DMC in a molar ratio of 1:1 into a three-necked flask, then adding a chain transfer agent 4-vinyl benzyl chloride, and reacting for 30 min at 55 DEG C;

[0071] S2, adding APS again, and reacting for 6 h at 60 DEG C; after the reaction is completed, the product is placed at room temperature, purified with 3 times the mass of ethanol, and a light yellow product is obtained; after being frozen and dried for 12 h, the pure CPA is obtained;

[0072] S3, graft copolymerizing LS as a skeleton with the prepared pure CPA; adding LS and CPA into a three-necked flask containing 1 mol / L NaOH, and reacting for 4 h at 70 DEG C; after the reaction is completed, the product is placed at room temperature, extracted with acetone for 3 times, and a brown product is obtained; after dialysis for 72 h, rotary evaporation and freezing and drying for 24 h, the purified LS-g-CPA is obtained.

[0073] The dry yeast powder is a dry powder prepared from Candida tropicalis.

[0074] A circle of yeast colonies on an agar slant is inoculated into a sterilized yeast extract-glucose YPD liquid medium in a flask, the flask is placed in a constant temperature shaker, and the yeast cell suspension is cultured at 28 DEG C and 175 rpm for 48 h; the cell suspension is centrifuged at 8000 rpm for 5 min, the supernatant is discarded, and the yeast precipitate is harvested; after being spray dried, the dry yeast powder is obtained.

[0075] After the yeast is cultured for 48 h, the YPD supernatant contains relevant acid protease, alpha-amylase and cellulase.

[0076] Example 3

[0077] The embodiment provides a sludge conditioner, which comprises the following components in parts by weight: moringa extract 25 parts, dry yeast powder 2 parts, tannic acid 12 parts, LS-g-CPA 35 parts, CS-g-PAO 20 parts, mercaptoethanol 1.5 parts and lysozyme 1.5 parts.

[0078] The embodiment provides a preparation method of a sludge conditioner, which comprises the following steps:

[0079] S1, the moringa extract, tannic acid, LS-g-CPA, CS-g-PAO and mercaptoethanol are weighed according to the formula amount, uniformly mixed, and then divided into small bags;

[0080] S2, the lysozyme and dry yeast powder are weighed according to the formula amount, and separately divided into small bags;

[0081] S3, when in use, the components in the three bags are mixed together to obtain the sludge conditioner.

[0082] Further, the preparation method of the moringa extract is as follows: the moringa seeds are dried in an oven at 45 DEG C for 48 h, then mixed and ground into fine powder to obtain the moringa extract.

[0083] The preparation method of the CS-g-PAO comprises the following steps: S1, dissolving chitosan in an acetic acid solution with a mass percentage of 1.0 wt% to obtain a chitosan solution with a mass percentage of 3.0 wt%, and stirring intensively to prepare the chitosan solution in a hot glass reaction container for standby;

[0084] S2, adding AO in an equal molar amount of the chitosan into the hot glass reaction container and stirring uniformly;

[0085] S3, removing oxygen in the hot glass reaction container by blowing nitrogen into the hot glass reaction container at room temperature for 10 min, and then adding VA-044 into the mixed solution;

[0086] S4, uniformly irradiating the hot glass reaction container with ultraviolet light with a power of 500 W and an optical intensity of 11.7 x 10 2 μw / cm 2 ; and

[0087] S5, purifying the obtained gel product with acetone and anhydrous ethanol, removing organic monomers and homopolymer PAO from the purified product with a Soxhlet extraction device (a mixture of formamide-acetic acid with a ratio of 1:1) and anhydrous ethanol, and drying in a vacuum oven to obtain the pure graft copolymer CS-g-PAO.

[0088] The preparation method of the LS-g-CPA comprises the following steps: S1, adding cationic monomers AM and DMC into a three-necked flask in a molar ratio of 1:1, and then adding a chain transfer agent 4-vinyl benzyl chloride, and reacting for 30 min at 55 DEG C;

[0089] S2, adding APS, and reacting for 6 h at 60 DEG C; after the reaction is completed, placing the product at room temperature, purifying the product with 3 times of mass of ethanol to obtain a light yellow product, and freeze-drying for 12 h to obtain the pure CPA;

[0090] S3, graft copolymerizing LS as a skeleton with the prepared pure CPA, adding LS and CPA into a three-necked flask containing 1 mol / L NaOH, and reacting for 4 h at 70 DEG C; after the reaction is completed, placing the product at room temperature, extracting the product with acetone for 3 times to obtain a brown product, and performing dialysis for 72 h, rotary evaporation and freeze-drying for 24 h to obtain the purified LS-g-CPA.

[0091] The dry yeast powder is a dry powder prepared from Candida tropicalis.

[0092] A loop of yeast colony on agar slant was inoculated into a flask of sterilized yeast extract- glucose YPD liquid medium, and the flask was placed in a constant temperature shaker at 28°C and 175 rpm for 48 hours to harvest a yeast cell suspension. The cell suspension was centrifuged at 8000 rpm for 5 min, and the supernatant was discarded. The yeast precipitate was harvested and spray-dried to obtain dry yeast powder.

[0093] After the yeast was cultured for 48 hours, the YPD supernatant contained relevant acid protease, a-amylase and cellulase.

[0094] Example 4

[0095] This example provides the application of the sludge conditioners in Examples 1-3 in deep dewatering of sludge, including the following steps: collecting activated sludge from the final settling tank of the Tianhe Municipal Sewage Treatment Plant in Guangzhou, filtering the fresh sludge through a 1 mm sieve to remove impurities, and then storing in a refrigerator at 4°C. 200 g of sludge was taken, and the sludge conditioner with a mass fraction of 5% was added to the sludge according to the amount of sludge, and mixed uniformly. The sludge was then treated for conditioning, and then dewatered by plate and frame filter press. The water content of the sludge and the content of bound water in the sludge were measured after dewatering. Examples 1-3 and Comparative Example 1 each used 200 g of sludge.

[0096] Comparative Example 1

[0097] This comparative example used a traditional sludge conditioner (polymeric ferric sulfate and quicklime at a ratio of 1:1).

[0098] Experimental Example 1

[0099] Determination of the water content of sludge

[0100] The water content of sludge refers to the weight loss of sludge dried to a constant weight at a certain temperature under atmospheric pressure at about 105°C or under reduced pressure.

[0101] The specific operation method is as follows: 60 ml of an evaporating dish was placed in an oven at a temperature of 105-110°C for 2 h, and then taken out and placed in a desiccator for cooling for 0.5 h. The weight was measured using a 10,000th scale balance and recorded as w1. 200 g of sludge was weighed using a tray balance and placed in the evaporating dish after drying, and then moved to a constant temperature water bath for evaporation. After evaporation, it was moved to an oven at a temperature of 105-110°C for continuous drying for 2 h, and then taken out and placed in a desiccator for cooling. After 0.5 h, the weight was measured. The above steps were repeated until the difference between the two weights was less than 0.0002 g, which was considered to be a constant weight, and recorded as w2. The calculation formula for the water content of the sludge is as follows:

[0102]

[0103] P = 100(w2 - w1) / w2

[0104] The sludge dewatering experiment of the sludge conditioners of Examples 1 to 3 and Comparative Example 1 was carried out according to the above method for measuring the moisture content of sludge, and the measured data of the moisture content of sludge are shown in Table 1.

[0105] Table 1 Measured results of the moisture content of sludge of the sludge conditioners of Examples 1 to 3 and Comparative Example 1

[0106] Group Sludge moisture content (%) Example 1 5.2％ Example 2 7.8％ Example 3 4.5％ Comparative Example 18.6％

[0107] From the experimental results of each example in Table 1, it can be seen that the sludge conditioners of Examples 1, 2 and 3 can effectively perform deep dewatering treatment on the sludge produced by the municipal sewage plant, and the moisture content of the dewatered sludge is below 10%, which indicates that the sludge conditioners of Examples 1 to 3 can remove the bound water contained in the sludge flocculation structure and improve the dewatering degree of the sludge. The comparative example uses the traditional sludge conditioner, and the moisture content of the dewatered sludge is above 10%, which is obviously worse than the sludge conditioners of Examples 1 to 3, and cannot improve the dewatering degree of the sludge.

[0108] Experimental Example 2

[0109] Measurement of the content of bound water in sludge

[0110] The measurement of the content of bound water in sludge was carried out by using a dilatometer. The experimental device was self-made according to the dilatometer used by Joyce K. Smith (Smith J. K., Vesilind P. A. Dilatometric measurement of bound Water in wastewater sludge. Water Research. 1995, 29(12): 2621-2626.), and was composed of a container with a stopper for containing sludge and a capillary tube with scales. The volume of the capillary tube between two adjacent scales was 0.005 mL.

[0111] The determination method is as follows: Accurately weigh the dilatometer, then add a sludge sample of known mass W1 to the container, ensuring that the height of the sludge sample does not exceed the bottom of the capillary tube. Add xylene with a known coefficient of shrinkage as an indicator liquid above the sludge sample until the xylene overflows the container. Stopper the container and secure it with a clamp. Accurately weigh the dilatometer again, calculate the mass W of the added xylene, and record the height H1 of the liquid level in the capillary tube and the operating temperature T1. Insert the dilatometer into a mixture of ethanol and dry ice, maintaining the temperature between -3 and -20°C. After stabilization, measure the temperature of the ethanol and dry ice mixture and record the height H2 of the liquid level in the capillary tube at this temperature.

[0112] The formula for calculating the mass of bound water in sludge is as follows:

[0113]

[0114] In the formula, Wb is the mass of bound water in the sludge sample, g; W1 is the total mass of water in the sludge sample, g; ΔV is the total volume change, mL; and μ1 is the xylene shrinkage coefficient, mL·g. -1 ·℃ -1 ΔT, temperature change, °C; μ2, coefficient of water shrinkage, mL·g -1 ·℃ -1 ;

[0115] Based on the above formula to calculate the mass of bound water in the sludge sample, the bound water content (%) is obtained using the following formula:

[0116]

[0117] Examples 1-3 and Comparative Example 1: Sludge dewatering experiments were conducted using the sludge conditioner. The sludge moisture content was measured according to the above method, and the sludge bound water content data are shown in Table 2 below.

[0118] Table 2 shows the results of sludge bound water content determination for sludge conditioners in Examples 1-3 and Comparative Example 1.

[0119] Group Sludge bound water content (%) Example 1 5.8 Example 2 3.2 Example 3 6.2 Comparative Example 13.5

[0120] As shown in Table 2, the sludge conditioners of Examples 1, 2, and 3 can effectively perform deep dewatering treatment on sludge produced by urban wastewater treatment plants. The bound water content of the sludge after dewatering is below 10%, indicating that the sludge conditioners of Examples 1-3 can remove the bound water contained in the sludge floc structure and improve the degree of sludge dewatering. In contrast, the traditional sludge conditioner used in the comparative example resulted in a bound water content of more than 10% in the sludge after dewatering treatment. Its dewatering effect was significantly worse than that of the sludge conditioners of Examples 1-3, as it could not remove the bound water in the floc structure and could not improve the degree of sludge dewatering.

[0121] The above embodiments are only the preferred embodiments of the present application, and cannot be used to limit the scope of protection of the present application. Any non-essential changes and substitutions made by those skilled in the art based on the present application shall fall within the scope of protection of the present application.

Claims

1. A sludge conditioner characterized by, It comprises the following components by weight parts: moringa extract 15-25 parts, dry yeast powder 2-5 parts, tannic acid 10-15 parts, LS-g-CPA 20-35 parts, CS-g-PAO 20-35 parts, mercaptoethanol 1-2 parts, lysozyme 1-2 parts; The preparation method of the CS-g-PAO comprises the following steps: S1, dissolve chitosan in 1.0 wt % acetic acid solution, stir vigorously to obtain a 3.0 wt % chitosan solution, and place in a hot glass reaction vessel for standby; S2, add AO in equimolar amount of chitosan to the hot glass reaction vessel and stir uniformly; S3, at room temperature, blow nitrogen into the hot glass reaction vessel for 10 min to remove oxygen in the hot glass reaction vessel, then add 2,20-azo[2-(2-imidazoline-2-yl)propane] dihydrochloride to the mixed solution; S4, use a 500W ultraviolet light with an intensity of 11.7×102μw / cm2 to uniformly irradiate the hot glass reaction vessel until the polymerization reaction is complete, and obtain a gel product; S5, the obtained gel product is purified with acetone and anhydrous ethanol, and after purification, a 1:1 formamide-acetic acid mixture and anhydrous ethanol are used to remove organic monomers and homopolymer PAO by Soxhlet extraction device, and the product is dried in a vacuum oven to obtain a pure graft copolymer CS-g-PAO; The preparation method of the LS-g-CPA comprises the following steps: S1, add cationic monomers AM and DMC in a molar ratio of 1:1 to a three-necked flask, then add chain transfer agent 4-vinyl benzyl chloride, and react at 55℃ for 30 min; S2, add APS, react at 60℃ for 6 h, after the reaction is completed, place the product at room temperature, purify with 3 times the mass of ethanol to obtain a light yellow product, and freeze-dry for 12 h to obtain a pure CPA; S3, graft copolymerize LS as a skeleton with the prepared pure CPA, add LS and CPA to a three-necked flask containing 1 mol / L NaOH, react at 70℃ for 4 h, after the reaction is completed, place the product at room temperature, extract with acetone 3 times to obtain a brown product, and after dialysis for 72 h, rotary evaporation, and freeze-drying for 24 h, obtain purified LS-g-CPA.

2. A sludge conditioner according to claim 1, characterised in that, The preparation method of the moringa extract is: dry the moringa seeds in an oven at 45℃ for 48 h, then mix and grind into fine powder to obtain the moringa extract.

3. A sludge conditioner according to claim 1, wherein The dry yeast powder is a dry powder made of Candida tropicalis.

4. A method of producing a sludge conditioner according to any one of claims 1 to 3, characterised in that, The preparation method comprises the following steps: S1, weigh the moringa extract, tannic acid, LS-g-CPA, CS-g-PAO, and mercaptoethanol according to the formula amount, mix uniformly, and then sub-pack into small bags; S2, weigh the lysozyme and dry yeast powder according to the formula amount, and sub-pack into small bags separately; S3, when used, take the components in three bags, mix together to obtain the sludge conditioner.

5. Use of a sludge conditioner according to any one of claims 1 to 3 for increasing the dewatering degree of sludge, characterized in that, The preparation method comprises the following steps: According to the amount of sludge, add 5% by mass of the sludge conditioner to the sludge, mix uniformly, and perform conditioning treatment on the sludge.

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